Linux Command Reference Shell Commands from A to Z (Michael Kofler) (Z-Library)
Technology
Linux users, your go-to desktop reference is here! Find practical commands for the Linux tasks you perform, from managing files to working with graphics systems to programming with Bash. Commands are grouped by topic and listed alphabetically to help you quickly find what you’re looking for, and options are listed for each entry to help you modify your commands. With detailed descriptions and practical examples, this guide doesn’t just tell you which commands to use—it shows you how to use them, too! Highlights include: 1) Syntax references 2) Keyboard shortcut references 3) File system and network administration 4) SELinux, AppArmor, iptables, and nft 5) Package management, snap, and flatpack 6) Printer, database, and server administration 7) Cloud and virtualization: aws, docker, kvm, and virsh 8) WLAN, Bluetooth, and other hardware 9) System start/stop, init system, and GRUB 10) acme.sh, certbot, and openssl certificates 11) Windows integration with wsl
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Rheinwerk Computing Explore more of the Rheinwerk Computing library! The Rheinwerk Computing series offers new and established professionals comprehen- sive guidance to enrich their skillsets and enhance their career prospects. Our publica- tions are written by the leading experts in their fields. Each book is detailed and hands-on to help readers develop essential, practical skills that they can apply to their daily work. Michael Kofler Linux: The Comprehensive Guide 2024, 1178 pages, paperback and e-book www.rheinwerk-computing.com/5779 Michael Kofler Scripting: Automation with Bash, PowerShell, and Python 2024, 470 pages, paperback and e-book www.rheinwerk-computing.com/5851 Bernd Öggl, Michael Kofler Docker: Practical Guide for Developers and DevOps Teams 2023, 491 pages, paperback and e-book www.rheinwerk-computing.com/5650 Bernd Öggl, Michael Kofler Git: Project Management for Developers and DevOps Teams 2023, 407 pages, paperback and e-book www.rheinwerk-computing.com/5555 Kofler, Gebeshuber, Kloep, Neugebauer, Zingsheim, Hackner, Widl, Aigner, Kania, Scheible, Wübbeling Hacking and Security: The Comprehensive Guide to Penetration Testing and Cybersecurity 2023, 1141 pages, paperback and e-book www.rheinwerk-computing.com/5696www.rheinwerk-computing.com
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Michael KoflerLinux Command Reference
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Contents at a Glance Overview of Commands Sorted by Topic ............................................................................. 7 Introduction .......................................................................................................................................... 25 Commands from A to Z .................................................................................................................. 27 #&%! (Special bash Characters) ................................................................................................ 425 Configuration Files ............................................................................................................................ 427 Keyboard Shortcuts .......................................................................................................................... 477 The Author ............................................................................................................................................. 491 Service Pages ...................................................................................................................................... I Legal Notes ............................................................................................................................................. II5
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Overview of Commands Sorted by Topic Managing Files Finding Files cat Combines multiple files into one file . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 cd Changes to another directory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 chgrp Changes the group membership of a file . . . . . . . . . . . . . . . . . . . . . . . . 69 chmod Changes the access bits of a file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 chown Changes the owner of a file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 cp Copies files. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 dircolors Helps with the configuration of the ls colors . . . . . . . . . . . . . . . . . . . . 95 erd Combines ls, tree, find, and du . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 file Attempts to determine the type of a file. . . . . . . . . . . . . . . . . . . . . . . . . 120 inotifywait Waits for file attributes to be changed . . . . . . . . . . . . . . . . . . . . . . . . . . 173 install Combines cp with chmod and chown. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174 j Changes to another directory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 ln Creates fixed and symbolic links to files . . . . . . . . . . . . . . . . . . . . . . . . . 197 ls Displays the table of contents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203 mkdir Creates a new directory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219 mv Moves files or changes their names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240 namei Shows the access rights of all directories of a file . . . . . . . . . . . . . . . . 248 rdfind Searches for and eliminates duplicates . . . . . . . . . . . . . . . . . . . . . . . . . . 308 rename Assigns new names to multiple files . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312 rm Deletes files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318 rmdir Deletes directories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320 rsync Synchronizes directories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324 stat Provides detailed information on files . . . . . . . . . . . . . . . . . . . . . . . . . . . 356 tee Duplicates the standard input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 370 touch Creates an empty file or changes the modify time . . . . . . . . . . . . . . . 376 tree Represents the directory hierarchy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379 truncate Reduces/enlarges a file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379 umask Controls which access rights new files and directories receive . . . 383 z Changes to another directory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 418 ack Serves as a grep alternative for programmers. . . . . . . . . . . . . . . . . . . . 28 erd Combines ls, tree, find, and du . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1127Personal Copy for raghunathan kumar, info@sierradigitalinc.com
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Overview of Commands Sorted by TopicCompressing and Archiving Files Processing Text Files find Searches for files by name, date, size, and so on . . . . . . . . . . . . . . . . . 121 fzf Enables an interactive search for files . . . . . . . . . . . . . . . . . . . . . . . . . . . 139 grep Searches for text in a text file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154 locate Searches for files in a database prepared for this purpose . . . . . . . . 199 updatedb Updates the search database for locate . . . . . . . . . . . . . . . . . . . . . . . . . 388 whereis Searches for files in predefined directories. . . . . . . . . . . . . . . . . . . . . . . 407 which Searches the PATH directories for commands. . . . . . . . . . . . . . . . . . . . . 407 bunzip2 Decompresses *.bz2 files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 bzip2 Compresses files; more powerful than gzip . . . . . . . . . . . . . . . . . . . . . 61 compress Compresses files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 cpio Transfers archive files between file systems . . . . . . . . . . . . . . . . . . . . . 80 gunzip Decompresses *.gz files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161 gzip Compresses files; more powerful than compress . . . . . . . . . . . . . . . . . 162 lz4 Compresses files; significantly faster than gzip . . . . . . . . . . . . . . . . . . 214 lzop Compresses files; significantly faster than gzip . . . . . . . . . . . . . . . . . . 214 tar Creates a *.tar archive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364 uncompress Decompresses files compressed using compress . . . . . . . . . . . . . . . . . 384 unxz Decompresses *.xz files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386 unzip Decompresses *.zip files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386 xz Compresses files; more powerful than bzip2 . . . . . . . . . . . . . . . . . . . . 417 zip Creates a Windows-compatible ZIP archive . . . . . . . . . . . . . . . . . . . . . . 420 zipinfo Displays the contents of a ZIP archive . . . . . . . . . . . . . . . . . . . . . . . . . . . 420 awk Programming language for text analysis . . . . . . . . . . . . . . . . . . . . . . . . 48 bat Displays a text file with syntax highlighting . . . . . . . . . . . . . . . . . . . . . 53 cat Outputs a file or combines multiple texts . . . . . . . . . . . . . . . . . . . . . . . 64 column Formats information column by column. . . . . . . . . . . . . . . . . . . . . . . . . 75 csplit Splits the text into individual files at predefined points . . . . . . . . . . 82 cut Extracts columns from each line of the text . . . . . . . . . . . . . . . . . . . . . 85 delta Compares two texts and highlights the differences in color . . . . . . 90 diff Compares two texts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 expand Replaces tab characters with spaces. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 fold Breaks down long lines of text into shorter ones . . . . . . . . . . . . . . . . . 131 fx Interactively scrolls through JSON files . . . . . . . . . . . . . . . . . . . . . . . . . . 138 grep Searches for texts within the file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154 head Outputs the first lines of the file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1648 © 2025 by Rheinwerk Publishing Inc., Boston (MA)
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Overview of Commands Sorted by TopicAccess Control Lists (ACLs) and Extended Attributes (EAs) Converters iconv Changes the character set of text files. . . . . . . . . . . . . . . . . . . . . . . . . . . 170 jq Extracts data from JSON documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 less Displays text files page by page (also backwards) . . . . . . . . . . . . . . . . 195 more Displays text files page by page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226 multitail Tracks the changes of multiple files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240 paste Combines multiple texts line by line . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281 patch Changes text files according to a diff file . . . . . . . . . . . . . . . . . . . . . . . 281 recode Converts between different character sets . . . . . . . . . . . . . . . . . . . . . . 311 sed Stream editor (programmable editor) . . . . . . . . . . . . . . . . . . . . . . . . . . . 331 sort Sorts files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348 split Splits a file into subfiles of a specified size . . . . . . . . . . . . . . . . . . . . . . . 350 strings Extracts character strings from binary files . . . . . . . . . . . . . . . . . . . . . . 357 tac Outputs text in reverse order, that is, the last line first . . . . . . . . . . . 363 tail Outputs the end of a file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363 tr Replaces predefined characters with other characters. . . . . . . . . . . . 377 unexpand Replaces spaces with tab characters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 384 uniq Eliminates multiple lines in a text file . . . . . . . . . . . . . . . . . . . . . . . . . . . 385 zcat Outputs a compressed text file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 419 zless Displays a compressed text file (also backwards). . . . . . . . . . . . . . . . . 419 zmore Displays a compressed text file page by page . . . . . . . . . . . . . . . . . . . . 419 attr Manages the additional attributes of a file . . . . . . . . . . . . . . . . . . . . . . 48 chacl Manages the ACLs of a file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 getcap Determines the capabilities of a file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139 getfacl Determines the ACLs of a file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140 getfattr Determines the additional attributes of a file . . . . . . . . . . . . . . . . . . . . 140 setcap Changes the capabilities of a file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333 setfacl Changes the ACLs of a file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 334 setfattr Changes the additional attributes of a file . . . . . . . . . . . . . . . . . . . . . . . 337 convert Converts graphic files. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 dvips Converts a DVI file into PostScript format . . . . . . . . . . . . . . . . . . . . . . . 108 enscript Converts text files into PostScript format . . . . . . . . . . . . . . . . . . . . . . . . 111 epstopdf Converts EPS files into PDF files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 exiftool Reads or changes Exif data in JPG files. . . . . . . . . . . . . . . . . . . . . . . . . . . 115 ffmpeg Converts video files. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 iconv Changes the character set of text files. . . . . . . . . . . . . . . . . . . . . . . . . . . 1709Personal Copy for raghunathan kumar, info@sierradigitalinc.com
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Overview of Commands Sorted by TopicManaging Processes lame Generates MP3-compatible audio files . . . . . . . . . . . . . . . . . . . . . . . . . . 193 magick Converts graphic files. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 mogrify Changes parameters of an image file. . . . . . . . . . . . . . . . . . . . . . . . . . . . 226 pandoc Creates documents from Markdown files. . . . . . . . . . . . . . . . . . . . . . . . 272 paps Converts UTF-8 text files to PostScript format . . . . . . . . . . . . . . . . . . . 274 pdf2ps Converts PDF files into PostScript files. . . . . . . . . . . . . . . . . . . . . . . . . . . 282 pdfimages Extracts images from PDF files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283 pdftk Manipulates PDF files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284 pdftops Serves as an alternative to pdf2ps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285 pdftotext Converts a PDF document into a plain text file . . . . . . . . . . . . . . . . . . . 286 pdfunite Merges several PDF files into a new document. . . . . . . . . . . . . . . . . . . 286 ps2pdf Converts PostScript files into PDF files. . . . . . . . . . . . . . . . . . . . . . . . . . . 296 recode Changes the character set of text files. . . . . . . . . . . . . . . . . . . . . . . . . . . 311 at Executes a job at a predefined time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 atq Lists jobs that are to be executed later . . . . . . . . . . . . . . . . . . . . . . . . . . 47 atrm Deletes a job that is to be executed later . . . . . . . . . . . . . . . . . . . . . . . . 48 batch Executes a job as soon as the system is idle . . . . . . . . . . . . . . . . . . . . . . 53 bg Continues a process in the background . . . . . . . . . . . . . . . . . . . . . . . . . . 54 chroot Starts a shell in a modified root directory . . . . . . . . . . . . . . . . . . . . . . . . 73 crontab Helps with the administration of custom crontab entries . . . . . . . . 80 disown Detaches a process from the shell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 fg Continues a process in the foreground . . . . . . . . . . . . . . . . . . . . . . . . . . 120 fuser Determines the program that accesses a file. . . . . . . . . . . . . . . . . . . . . 136 glances Modern alternative to top . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148 halt Quits Linux and stops the computer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 history Displays the last commands executed in the bash . . . . . . . . . . . . . . . 165 htop Displays a list of all processes every five seconds. . . . . . . . . . . . . . . . . 167 iftop Monitors the network activity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 ionice Controls the I/O priority of a process . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176 iotop Shows the processes with the highest I/O activity . . . . . . . . . . . . . . . 177 kill Sends signals (usually to terminate processes) . . . . . . . . . . . . . . . . . . . 191 killall Like kill; mentions the process by name . . . . . . . . . . . . . . . . . . . . . . . . 192 ldconfig Updates the cache file for the library search . . . . . . . . . . . . . . . . . . . . . 194 ldd Provides all required libraries of a program . . . . . . . . . . . . . . . . . . . . . . 195 lsof Lists open files and the assigned processes . . . . . . . . . . . . . . . . . . . . . . 209 nice Starts a program with reduced priority . . . . . . . . . . . . . . . . . . . . . . . . . . 260 nohup Starts a process that is detached from the shell . . . . . . . . . . . . . . . . . . 265 parallel Starts multiple similar jobs in parallel . . . . . . . . . . . . . . . . . . . . . . . . . . . 27410 © 2025 by Rheinwerk Publishing Inc., Boston (MA)
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Overview of Commands Sorted by TopicManaging Users and Groups pidof Determines the process number of a program . . . . . . . . . . . . . . . . . . . 287 powertop Analyzes the energy consumption of running processes. . . . . . . . . . 292 ps Displays the list of running processes . . . . . . . . . . . . . . . . . . . . . . . . . . . 294 pstree Like ps; makes the dependencies more visible . . . . . . . . . . . . . . . . . . . 298 reboot Quits Linux and reboots the computer . . . . . . . . . . . . . . . . . . . . . . . . . . 311 renice Changes the priority of a running process . . . . . . . . . . . . . . . . . . . . . . . 313 sudo Runs a program as root. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 358 timeout Limits the execution time of a command . . . . . . . . . . . . . . . . . . . . . . . . 375 top Displays a list of all processes every five seconds. . . . . . . . . . . . . . . . . 376 uptime Shows how long the computer has been running . . . . . . . . . . . . . . . . 388 watch Executes a command periodically and displays the output . . . . . . . 403 addgroup Sets up a new group (Debian/Ubuntu) . . . . . . . . . . . . . . . . . . . . . . . . . . 32 adduser Sets up a new user (Debian/Ubuntu) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 chage Changes the expiration date of an account or password . . . . . . . . . 65 chgrp Changes the group membership of a file . . . . . . . . . . . . . . . . . . . . . . . . 69 chown Changes the owner of a file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 chpasswd Changes a user password without interaction . . . . . . . . . . . . . . . . . . . 72 chsh Changes the default shell of a user . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 delgroup Deletes a group (Debian/Ubuntu) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 deluser Deletes a user (Debian/Ubuntu) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 groupadd Sets up a new group . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 groupdel Deletes a group . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 groupmod Changes group properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 groups Displays the groups of the current user. . . . . . . . . . . . . . . . . . . . . . . . . . 160 gpasswd Changes group passwords . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 id Displays the current user and group ID . . . . . . . . . . . . . . . . . . . . . . . . . . 170 last Reveals who was last logged in on this computer . . . . . . . . . . . . . . . . 194 lastb Lists which login attempts have recently failed . . . . . . . . . . . . . . . . . . 194 makepasswd Generates a new, random password . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216 mkpasswd Generates a new, random password (CentOS, Fedora, RHEL). . . . . . 224 newgrp Changes the active group of a user . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254 newusers Sets up multiple new users . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254 passwd Changes the password of a user. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280 pwgen Generates easy-to-remember passwords . . . . . . . . . . . . . . . . . . . . . . . . 300 useradd Sets up a new user . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 389 userdel Deletes a user . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 389 usermod Changes user properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 390 vigr Edits /etc/groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39311Personal Copy for raghunathan kumar, info@sierradigitalinc.com
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Overview of Commands Sorted by TopicAdministrating the File System vipw Edits /etc/passwd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393 visudo Edits /etc/sudoers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393 who Provides information about the logged-in users . . . . . . . . . . . . . . . . . 408 badblocks Tests whether data carriers contain defective sectors . . . . . . . . . . . . 52 blkid Returns the UUID and the name of a file system . . . . . . . . . . . . . . . . . 55 btrfs Administrates a Btrfs file system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 cfdisk Partitions a hard disk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 cryptsetup Sets up an encrypted device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 dd Copies data blocks between devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 df Displays the free memory on the hard disk . . . . . . . . . . . . . . . . . . . . . . 91 du Determines the space requirement of a directory . . . . . . . . . . . . . . . . 106 dumpe2fs Displays internal information about an ext file system . . . . . . . . . . . 107 e4defrag Defragments files of an ext4 file system. . . . . . . . . . . . . . . . . . . . . . . . . 108 exfatlabel Changes the name of an exFAT file system . . . . . . . . . . . . . . . . . . . . . . 115 findmnt Provides a list of all active file systems . . . . . . . . . . . . . . . . . . . . . . . . . . 125 fstrim Reports all free data blocks to the SSD. . . . . . . . . . . . . . . . . . . . . . . . . . . 134 kpartx Creates or deletes device files for virtual data carriers . . . . . . . . . . . . 192 lsblk Lists all block devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206 mdadm Manages RAID partitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217 mkfifo Creates a FIFO file (a named pipe) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219 mkfs Sets up a file system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220 mknod Creates device files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224 mkswap Sets up a file or partition as a swap area. . . . . . . . . . . . . . . . . . . . . . . . . 225 mount Integrates a file system into the directory tree . . . . . . . . . . . . . . . . . . . 226 ncdu Serves as an interactive, convenient du variant. . . . . . . . . . . . . . . . . . . 250 parted Partitions a hard disk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275 partprobe Informs the kernel about the changed partitioning . . . . . . . . . . . . . . 278 partx Reads partitions or changes the partition table of the kernel . . . . . 279 resize2fs Changes the size of an ext file system . . . . . . . . . . . . . . . . . . . . . . . . . . . 313 sfdisk Partitions a hard disk with an MBR partition table . . . . . . . . . . . . . . . 339 sgdisk Partitions a hard disk with a GUID partition table . . . . . . . . . . . . . . . . 340 smartctl Controls the SMART functions of the hard disk . . . . . . . . . . . . . . . . . . 344 snapper Manages Btrfs snapshots (SUSE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347 swapon Deactivates a swap file or partition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360 swapoff Activates a swap file or partition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360 sync Executes all buffered write operations . . . . . . . . . . . . . . . . . . . . . . . . . . 360 tune2fs Changes system parameters of an ext file system. . . . . . . . . . . . . . . . 380 umount Removes a file system from the directory tree . . . . . . . . . . . . . . . . . . . 38312 © 2025 by Rheinwerk Publishing Inc., Boston (MA)
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Overview of Commands Sorted by TopicLogical Volume Manager (LVM) SELinux and AppArmor xfs_admin Changes parameters of an XFS file system . . . . . . . . . . . . . . . . . . . . . . . 413 xfs_growfs Enlarges an XFS file system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414 xfs_info Displays the key data of an XFS file system . . . . . . . . . . . . . . . . . . . . . . 414 xfs_repair Repairs a defective XFS file system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414 zramctl Controls the ZRAM swap memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 420 lvcreate Sets up a new logical volume (LV) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211 lvdisplay Provides detailed information about an LV . . . . . . . . . . . . . . . . . . . . . . 212 lvextend Enlarges an LV. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 lvm Serves as an LVM basic command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 lvreduce Reduces the size of an LV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 lvremove Deletes an LV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 lvrename Assigns a new name to the LV. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 lvscan Lists all LVs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 pvcreate Identifies a partition as a physical volume (PV). . . . . . . . . . . . . . . . . . . 298 pvdisplay Provides detailed information about a PV . . . . . . . . . . . . . . . . . . . . . . . 299 pvremove Removes the PV identification of an unused PV . . . . . . . . . . . . . . . . . . 299 pvscan Lists all PVs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299 vgchange Changes the attributes of a volume group (VG) . . . . . . . . . . . . . . . . . . 391 vgcreate Creates a new VG from one or more PVs. . . . . . . . . . . . . . . . . . . . . . . . . 391 vgdisplay Provides detailed information about a VG . . . . . . . . . . . . . . . . . . . . . . . 392 vgextend Increases a VG by one PV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392 vgmerge Combines two VGs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392 vgreduce Reduces a VG by one unused PV. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392 vgrename Assigns a new name to a VG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392 vgscan Lists all VGs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393 aa-complain Logs AppArmor rule violations without penalizing them . . . . . . . . . 27 aa-disable Deactivates an AppArmor rule profile . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 aa-enforce Ensures compliance with AppArmor rules . . . . . . . . . . . . . . . . . . . . . . . 27 aa-status Determines the status of the AppArmor system . . . . . . . . . . . . . . . . . 27 chcon Changes the SELinux context of files . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 getenforce Determines the SELinux mode (Enforcing or Permissive) . . . . . . . . 140 restorecon Restores the default SELinux context . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315 sealert Helps to analyze SELinux rule violations . . . . . . . . . . . . . . . . . . . . . . . . . 330 sestatus Determines the status of the SELinux system . . . . . . . . . . . . . . . . . . . . 33213Personal Copy for raghunathan kumar, info@sierradigitalinc.com
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Overview of Commands Sorted by TopicPackage Management Network Administration setenforce Changes the SELinux mode between Enforcing and Permissive 334 setsebool Changes Boolean parameters of the SELinux rules . . . . . . . . . . . . . . . 338 apk Manages packages in Alpine Linux . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 apt Helps with DEB package management (Debian, Ubuntu) . . . . . . . . . 38 add-apt-repository Sets up a PPA package source (Ubuntu). . . . . . . . . . . . . . . . . . . . . . . . . . 31 alien Converts packages between different formats . . . . . . . . . . . . . . . . . . . 33 alternatives Sets up links in /etc/alternatives (Fedora, Red Hat) . . . . . . . . . . . . 35 apt-cache Provides information about installed/available packages . . . . . . . . 39 apt-get Helps with DEB package management (Debian, Ubuntu) . . . . . . . . . 41 apt-file Searches for files even in uninstalled packages (Debian, Ubuntu) 40 apt-key Sets up a key for an APT package source . . . . . . . . . . . . . . . . . . . . . . . . . 42 aptitude Helps with DEB package management . . . . . . . . . . . . . . . . . . . . . . . . . . 43 cnf Reveals which package contains a command (SUSE) . . . . . . . . . . . . . 75 dnf Serves as an alternative to yum (Fedora). . . . . . . . . . . . . . . . . . . . . . . . . . 97 dpkg (De)installs or updates DEB packages. . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 flatpak Manages Flatpak packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 pacman Manages packages from Arch Linux . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270 pip Manages Python packages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289 pkcon Manages packages across distributions (PackageKit) . . . . . . . . . . . . . 290 ppa-purge Deactivates a PPA package source (Ubuntu) . . . . . . . . . . . . . . . . . . . . . 293 pro Controls Ubuntu Pro functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293 rpm (De)installs or updates RPM packages . . . . . . . . . . . . . . . . . . . . . . . . . . . 322 rpm2archive Converts a package into a TAR archive. . . . . . . . . . . . . . . . . . . . . . . . . . . 324 rpm2cpio Converts a package into a CPIO archive . . . . . . . . . . . . . . . . . . . . . . . . . . 324 snap Manages snap packages (Ubuntu) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347 tasksel (De)installs DEB package groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 367 ubuntu-security- status Indicates the support period of the installed packages . . . . . . . . . . . 381 update-alternatives Sets up links in /etc/alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386 yay Manages Arch Linux packages including AUR . . . . . . . . . . . . . . . . . . . . 418 yum Helps with RPM package management (Fedora, Red Hat) . . . . . . . . 418 zypper Helps with RPM package management (SUSE) . . . . . . . . . . . . . . . . . . . 421 cadaver Transfers files interactively via WebDAV. . . . . . . . . . . . . . . . . . . . . . . . . 62 curl Transfers files from/to HTTP, FTP, and SSH servers . . . . . . . . . . . . . . . 84 dhclient Performs a DHCP network configuration . . . . . . . . . . . . . . . . . . . . . . . . 9314 © 2025 by Rheinwerk Publishing Inc., Boston (MA)
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Overview of Commands Sorted by Topicdig Performs DNS queries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 etherwake Activates a Wake-on-LAN device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 ethtool Changes the parameters of an Ethernet adapter . . . . . . . . . . . . . . . . . 114 exportfs Reports the NFS configuration to the NFS server . . . . . . . . . . . . . . . . . 117 firewall-cmd Reads or changes the firewall configuration (RHEL/Fedora). . . . . . . 126 ftp Interactively transfers files via FTP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 host Resolves IP addresses or network names . . . . . . . . . . . . . . . . . . . . . . . . 165 hostname Returns or changes the name of the local computer . . . . . . . . . . . . . 166 hostnamectl Changes the host name permanently . . . . . . . . . . . . . . . . . . . . . . . . . . . 166 ifconfig Configures a network interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 ifdown Deactivates a network interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172 ifup Activates a network interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172 ip Displays or changes network settings . . . . . . . . . . . . . . . . . . . . . . . . . . . 177 ipcalc Calculates network areas and masks . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 iptables Configures a Netfilter firewall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 ip[6]tables-restore Reads multiple firewall rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183 ip[6]tables-save Outputs all firewall rules in text format . . . . . . . . . . . . . . . . . . . . . . . . . 183 ip[6]tables-xml Outputs all firewall rules as an XML document . . . . . . . . . . . . . . . . . . 183 iw Controls WLAN interfaces. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184 mtr Combines ping and traceroute results . . . . . . . . . . . . . . . . . . . . . . . . . . 239 nft Configures an nftables firewall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255 netplan Controls other network backends (Ubuntu). . . . . . . . . . . . . . . . . . . . . . 251 netstat Analyzes the network activity of the local computer . . . . . . . . . . . . . 251 networkctl Provides the network status (systemd) . . . . . . . . . . . . . . . . . . . . . . . . . . 252 newaliases Reports changes in /etc/aliases to the mail server. . . . . . . . . . . . . . 254 nmap Analyzes the network activity of a foreign computer . . . . . . . . . . . . . 260 nmblookup Determines the NetBIOS names of SMB servers . . . . . . . . . . . . . . . . . . 263 nmcli Controls the NetworkManager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264 openssl Generates and administers SSL key files . . . . . . . . . . . . . . . . . . . . . . . . . 266 ping Checks the network connection to a computer. . . . . . . . . . . . . . . . . . . 289 pnuke Terminates a program in parallel on several hosts . . . . . . . . . . . . . . . 297 postconf Reads or changes the postfix configuration. . . . . . . . . . . . . . . . . . . . . . 291 postqueue Displays the postfix queue. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292 pscp Copies files simultaneously from/to host(s) . . . . . . . . . . . . . . . . . . . . . 297 pssh Executes commands on several hosts via SSH. . . . . . . . . . . . . . . . . . . . 297 rdiff-backup Creates incremental backups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310 resolvectl Determines or changes the DNS configuration. . . . . . . . . . . . . . . . . . . 314 rfkill (De)activates Bluetooth, WLAN, and mobile radio adapters. . . . . . . 316 route Changes or displays the IP routing table . . . . . . . . . . . . . . . . . . . . . . . . . 321 rpcinfo Provides information about RPC and NFS services. . . . . . . . . . . . . . . . 322 rsync Synchronizes network directories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324 scp Transfers files encrypted via SSH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32715Personal Copy for raghunathan kumar, info@sierradigitalinc.com
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Overview of Commands Sorted by TopicHacking and Security Printer, Database, and Server Administration sftp Transfers files via SFTP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 340 showmount Lists NFS directories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342 smbclient Transfers files from Windows network directories . . . . . . . . . . . . . . . 345 smbpasswd Sets the password of a Samba account . . . . . . . . . . . . . . . . . . . . . . . . . . 346 smbstatus Provides status information of the local Samba server . . . . . . . . . . . 346 ss Analyzes the network activity of the local computer . . . . . . . . . . . . . 351 ssh Enables logins on other computers in the network . . . . . . . . . . . . . . . 352 ssh-keygen Generates and manages SSH keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 355 ssh-copy-id Transmits a public key to the SSH server. . . . . . . . . . . . . . . . . . . . . . . . . 354 swaks Helps with testing and debugging mail servers . . . . . . . . . . . . . . . . . . 359 telnet Communicates interactively with a network service . . . . . . . . . . . . . 370 traceroute[6] Provides the intermediate stations for a network address . . . . . . . . 377 ufw Configures the firewall (Ubuntu) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 381 wakeonlan Activates a Wake-on-LAN device (Debian, Ubuntu). . . . . . . . . . . . . . . 403 wget Downloads files or directories. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 404 whois Performs DNS queries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408 wol Activates a Wake-on-LAN device (Fedora, Red Hat) . . . . . . . . . . . . . . . 409 wpa_passphrase Helps with the WLAN configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 410 arp Manages the ARP cache . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 arp-scan Sends ARP packets to all addresses in a network . . . . . . . . . . . . . . . . . 45 chkrootkit Searches for known rootkits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 fail2ban-client Administrates Fail2ban . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 hydra Serves as an online password cracker. . . . . . . . . . . . . . . . . . . . . . . . . . . . 168 john Serves as an offline password cracker . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 nc Netcat, redirects network data to the standard input or output . . 248 ngrep Filters network streams using grep (packet sniffing) . . . . . . . . . . . . . 259 nmap Serves as a network and port scanner . . . . . . . . . . . . . . . . . . . . . . . . . . . 260 rkhunter Searches for known rootkits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 317 tcpdump Filters network streams (packet sniffing) . . . . . . . . . . . . . . . . . . . . . . . . 368 acme.sh Manages certificates from Let’s Encrypt . . . . . . . . . . . . . . . . . . . . . . . . . 29 htpasswd Saves Apache login data in a password file . . . . . . . . . . . . . . . . . . . . . . 167 lpadmin Sets up new printers or deletes them again. . . . . . . . . . . . . . . . . . . . . . 201 lpinfo Lists all print devices, printer drivers, and so on . . . . . . . . . . . . . . . . . . 201 lpoptions Displays or changes the printer options . . . . . . . . . . . . . . . . . . . . . . . . . 20216 © 2025 by Rheinwerk Publishing Inc., Boston (MA)
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Overview of Commands Sorted by TopicAudio Functions and Hardware Management lpq Displays the contents of a printer queue . . . . . . . . . . . . . . . . . . . . . . . . 202 lpr Prints a file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202 lprm Deletes a print job from the queue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203 lpstat Provides information about printers, print jobs, and so on. . . . . . . . 203 mysql Executes SQL commands on a MySQL server . . . . . . . . . . . . . . . . . . . . . 241 mysqladmin Helps with MySQL administration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243 mysqlbinlog Extracts data from binary MySQL logging files . . . . . . . . . . . . . . . . . . . 245 mysqldump Performs a MySQL backup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245 pg_dump Creates a backup of a PostgreSQL database. . . . . . . . . . . . . . . . . . . . . . 286 psql Executes SQL commands on a PostgreSQL server. . . . . . . . . . . . . . . . . 296 smbpasswd Changes a Samba password . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 346 sqlite3 Executes SQL commands in SQLite databases. . . . . . . . . . . . . . . . . . . . 351 acpi Provides information about the battery status. . . . . . . . . . . . . . . . . . . 31 alsactl Saves or loads all parameters of the audio system . . . . . . . . . . . . . . . 33 alsamixer Interactively adjusts the audio channels . . . . . . . . . . . . . . . . . . . . . . . . . 34 amixer Controls the audio channels through options . . . . . . . . . . . . . . . . . . . . 35 boltctl Controls devices on the Thunderbolt interface . . . . . . . . . . . . . . . . . . . 57 free Displays the free memory space (RAM/Swap). . . . . . . . . . . . . . . . . . . . 132 fwupdmgr Manages firmware updates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137 hwclock Reads or sets the hardware clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168 inxi Provides an overview of the hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 kbdrate Sets the key repetition rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190 localectl Changes the language and keyboard settings. . . . . . . . . . . . . . . . . . . . 198 lscpu Provides information about the CPU . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208 lshw Creates a hierarchical list of hardware components . . . . . . . . . . . . . . 208 lspci Provides information about PCI components . . . . . . . . . . . . . . . . . . . . 210 lsscsi Provides information about connected SCSI devices. . . . . . . . . . . . . . 210 lsusb Provides information about connected USB devices . . . . . . . . . . . . . . 211 nproc Provides the number of CPU cores. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266 pactl Controls the PulseAudio server. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271 paplay Plays a raw file via PulseAudio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273 parecord Performs a raw audio recording via PulseAudio . . . . . . . . . . . . . . . . . . 273 powertop Helps to optimize the energy consumption of notebooks. . . . . . . . . 292 pw-cat Transfers audio files from or to the PipeWire system . . . . . . . . . . . . . 299 pw-cli Controls the PipeWire system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299 pw-mon Lists all PipeWire objects. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299 pw-top Displays the active PipeWire audio components . . . . . . . . . . . . . . . . . 299 speaker-test Tests the audio system and the connected speakers . . . . . . . . . . . . . 349 timedatectl Sets the date, time, and time zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37417Personal Copy for raghunathan kumar, info@sierradigitalinc.com
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Overview of Commands Sorted by TopicBluetooth Kernel System Start and Stop, init System, Logging, and GRUB vcgencmd Reads or changes hardware parameters of Raspberry Pi . . . . . . . . . . 390 bluetoothctl Configures Bluetooth devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 hciconfig (De)activates local Bluetooth adapters . . . . . . . . . . . . . . . . . . . . . . . . . . 163 hcitool Manages Bluetooth devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 l2ping Sends echo requests to Bluetooth devices . . . . . . . . . . . . . . . . . . . . . . . 193 rfkill (De)activates Bluetooth, WLAN, and mobile radio adapters. . . . . . . 316 sdptool Determines detailed information about Bluetooth devices . . . . . . . 329 canonical-livepatch Administrates kernel live patches (Ubuntu). . . . . . . . . . . . . . . . . . . . . . 62 depmod Creates a file with all module dependencies . . . . . . . . . . . . . . . . . . . . . 91 dmesg Displays the messages of the kernel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 dracut Creates a new initrd file (Fedora, RHEL, SUSE) . . . . . . . . . . . . . . . . . . . . 106 insmod Loads a kernel module (low level) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174 kexec Activates a different kernel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190 lsmod Lists all loaded kernel modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 modinfo Provides information on a kernel module . . . . . . . . . . . . . . . . . . . . . . . . 225 modprobe Loads a kernel module, including dependencies. . . . . . . . . . . . . . . . . . 225 uname Displays the current kernel version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 384 update-initramfs Creates a new initrd file (Debian, Ubuntu) . . . . . . . . . . . . . . . . . . . . . . . 387 efibootmgr Reads or changes the table of EFI boot entries . . . . . . . . . . . . . . . . . . . 109 grub-install Installs GRUB into the boot sector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160 grub-mkconfig Creates a new GRUB configuration file . . . . . . . . . . . . . . . . . . . . . . . . . . 161 journalctl Reads news from the journal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188 logger Logs a message. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199 loginctl Controls the systemd login manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200 needs-restarting Reveals whether the system or individual services need to be restarted. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250 shutdown Terminates Linux. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342 systemctl Manages systemd processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361 systemd-analyze Helps with systemd troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363 update-grub Updates the GRUB configuration (Debian, Ubuntu) . . . . . . . . . . . . . . 38718 © 2025 by Rheinwerk Publishing Inc., Boston (MA)
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Overview of Commands Sorted by TopicVirtualization, Containers, Cloud Terminal and Text Console Online Help Graphics System and Gnome aws Controls Amazon cloud services. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 docker Manages containers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 kvm Runs a virtual machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193 podman Docker, manages containers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 qemu Runs a virtual machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302 qemu-img Creates or edits image files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306 rclone Synchronizes a local directory with a cloud directory . . . . . . . . . . . . . 307 virsh Executes libvirt commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393 virt-clone Creates a copy of a virtual machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 399 virt-install Sets up a new virtual machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400 virt-viewer Allows the operation of a virtual machine via VNC . . . . . . . . . . . . . . . 402 wsl Manages Linux installations on Windows . . . . . . . . . . . . . . . . . . . . . . . 410 echo Outputs one line of text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 loadkeys Loads a keyboard table for text consoles. . . . . . . . . . . . . . . . . . . . . . . . . 197 printf Enables a formatted output as under C . . . . . . . . . . . . . . . . . . . . . . . . . . 293 reset Performs a reset for the terminal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313 screen Manages several sessions in one terminal . . . . . . . . . . . . . . . . . . . . . . . 328 setterm Changes various terminal settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338 apropos Searches for commands on a topic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 help Displays the description of a shell command . . . . . . . . . . . . . . . . . . . . 165 info Starts the info system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172 man Displays the description of a command. . . . . . . . . . . . . . . . . . . . . . . . . . 216 tldr Displays examples of the use of a command. . . . . . . . . . . . . . . . . . . . . 375 whatis Displays a short description of a command . . . . . . . . . . . . . . . . . . . . . . 406 chvt Changes the active text console or activates the graphics system 74 dconf Modifies the dconf database (low level) . . . . . . . . . . . . . . . . . . . . . . . . . 87 fc-list Lists all scalable fonts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 fgconsole Returns the number of the active console . . . . . . . . . . . . . . . . . . . . . . . 120 gnome-session-quit Initiates a logout or shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14919Personal Copy for raghunathan kumar, info@sierradigitalinc.com
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Overview of Commands Sorted by TopicMiscellaneous grim Creates a screenshot on Wayland . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158 gsettings Reads or changes settings of the dconf database . . . . . . . . . . . . . . . . 161 nvidia-xconfig Helps with the configuration of the NVIDIA graphics driver . . . . . . 266 xdg-open Opens a file with a suitable program . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413 scrot Creates a screenshot under X . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328 slurp Enables the selection of a rectangle on Wayland . . . . . . . . . . . . . . . . . 343 wl-copy Inserts data into the Wayland clipboard . . . . . . . . . . . . . . . . . . . . . . . . . 409 wl-paste Reads data from the Wayland clipboard . . . . . . . . . . . . . . . . . . . . . . . . . 409 wlr.randr Changes the resolution of the graphics system (Wayland). . . . . . . . 409 xdg-open Opens a file using a suitable program . . . . . . . . . . . . . . . . . . . . . . . . . . . 413 xdpyinfo Provides information on the running X server. . . . . . . . . . . . . . . . . . . . 413 xhost Allows or blocks hosts for the X login . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415 xinput Configures input devices for X . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415 xkill Terminates a program with a mouse click . . . . . . . . . . . . . . . . . . . . . . . 415 xrandr Changes the resolution of the graphics system (X) . . . . . . . . . . . . . . . 416 xset Changes user settings of the graphics system (X) . . . . . . . . . . . . . . . . 417 zenity Displays simple graphical dialogs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 419 alias Defines an abbreviation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 basename Determines the file name of a path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 bc Performs simple calculations (like a pocket calculator) . . . . . . . . . . . 54 cksum Calculates the CRC checksum for a file . . . . . . . . . . . . . . . . . . . . . . . . . . 74 date Displays the date and time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 dirname Determines the directory of a path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 expr Performs calculations and sample comparisons. . . . . . . . . . . . . . . . . . 117 git Controls the version management system Git . . . . . . . . . . . . . . . . . . . 142 gpioget Reads the state of the input/output pins of Raspberry Pi . . . . . . . . . 153 gpioset Changes the state of the input/output pins of Raspberry Pi . . . . . . 153 hash Displays the hash table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 ldd Displays the required libraries for a program . . . . . . . . . . . . . . . . . . . . 195 lsb_release Determines the name and version of the distribution . . . . . . . . . . . . 207 mail Transfers an email to the local mail server . . . . . . . . . . . . . . . . . . . . . . . 215 md5sum Calculates a checksum for a file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217 printenv Displays only the environment variables . . . . . . . . . . . . . . . . . . . . . . . . 293 pinctrl Controls the input/output pins of Raspberry Pi . . . . . . . . . . . . . . . . . . 287 qalc Serves as a calculator for the terminal . . . . . . . . . . . . . . . . . . . . . . . . . . . 301 rpicam-still Takes a photo (Raspberry Pi OS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318 rpicam-vid Records a video (Raspberry Pi OS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320 seq Returns a numerical sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33220 © 2025 by Rheinwerk Publishing Inc., Boston (MA)
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Overview of Commands Sorted by Topic“bash” Programming “bash” Variable Management set Displays all variables known to the shell. . . . . . . . . . . . . . . . . . . . . . . . . 333 sha Calculates a checksum for a file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341 sleep Waits for a specified time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 343 strace Reveals which functions a program calls . . . . . . . . . . . . . . . . . . . . . . . . 357 time Measures the execution time of a command . . . . . . . . . . . . . . . . . . . . 373 tty Displays the device name of the terminal. . . . . . . . . . . . . . . . . . . . . . . . 380 type Specifies the type of a command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 380 unalias Deletes an abbreviation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 384 uname Returns the operating system name and the kernel version . . . . . . 384 xargs Redirects the standard input to a command . . . . . . . . . . . . . . . . . . . . . 412 break Ends a loop prematurely . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 case Initiates a case differentiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 continue Skips the loop body . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 exit Terminates the shell program. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 for Initiates a loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132 function Defines a new function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 getopts Processes options passed to a script . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141 if Initiates a branch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 local Defines local variables in a function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198 source Runs the specified shell file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349 test Analyzes a condition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371 until Initiates a loop (variant 1). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 385 while Initiates a loop (variant 2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 407 alias Defines an abbreviation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 declare Defines an environment variable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 export Defines a specified shell variable as an environment variable. . . . . 116 local Defines local variables in a function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198 read Imports a variable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311 readonly Displays all read-only variables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311 shift Moves the parameter list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342 unalias Deletes an abbreviation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 384 unset Deletes a variable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38521Personal Copy for raghunathan kumar, info@sierradigitalinc.com
The above is a preview of the first 20 pages. Register to read the complete e-book.
AI Reading Assistant
Whole-book reading guide from stratified index samples; jump to passages in the text
AI guide
【One-Line Pitch】
A comprehensive, alphabetically organized desktop reference for Linux command-line users, covering everything from basic file operations to advanced system administration, security, and cloud tools—ideal for sysadmins, developers, and power users who need quick, practical answers.
【Book Arc】
- **Opening (~0%–10%)**: Introduces the book's structure and purpose, with a topic-sorted overview of commands. Early sections cover fundamental file and directory operations (ls, cp, mv, rm, mkdir, chmod, chown) and basic search tools (find, grep, locate), establishing the core vocabulary for daily Linux work.
- **Early (~10%–30%)**: Expands into text processing utilities (sed, sort, diff, cut, paste, tr, uniq) and file conversion tools (iconv, jq, pdftotext). Introduces process and job management (ps, kill, bg, fg, crontab, at), along with system monitoring tools (htop, glances, iotop) for understanding and controlling running tasks.
- **Early–Middle (~30%–40%)**: Covers user and group administration (useradd, usermod, passwd, group management) and begins file system administration with tools for checking disks (badblocks, blkid) and understanding device structure.
- **Middle (~40%–60%)**: Delves into advanced file system management, including partitioning (cfdisk), file system creation (mkfs), RAID (mdadm), LVM (pvcreate, vgcreate, lvcreate), and encryption (cryptsetup). Introduces security frameworks SELinux and AppArmor with their respective management commands.
- **Late (~60%–100%)**: Moves to higher-level administration: package management (apk, snap, flatpak), network configuration and security (iptables, nft), server administration (printers, databases), cloud and virtualization tools (aws, docker, kvm, virsh), and system boot management (GRUB, init systems). Concludes with certificate management (openssl, certbot) and Windows integration via WSL.
【Key Takeaways】
- **File operations form the foundation** (Opening): Mastery of ls, cp, mv, rm, chmod, and chown is non-negotiable for any Linux user; the book provides syntax and options for each, making it a reliable reference for everyday tasks.
- **Text processing is a superpower** (Early): Tools like sed, awk (implied), sort, and uniq enable powerful data manipulation directly from the command line, reducing the need for scripting or GUI tools.
- **Process control requires understanding signals** (Early): Commands like kill, killall, and nohup manage running programs; knowing the difference between foreground, background, and detached processes is essential for efficient terminal work.
- **User management is security-critical** (Early–Middle): Proper use of useradd, usermod, and passwd, combined with sudo configuration via visudo, ensures system access is controlled and auditable.
- **File system administration demands a layered approach** (Middle): From partitioning (cfdisk) to file system creation (mkfs) to logical volume management (LVM), each layer has dedicated tools; understanding the hierarchy (PV → VG → LV) is key to flexible storage.
- **Security frameworks require active management** (Middle): SELinux and AppArmor are not set-and-forget; tools like setenforce, restorecon, and aa-status help administrators monitor and adjust policies without disabling protection entirely.
- **Modern Linux extends beyond the local machine** (Late): Package managers (snap, flatpak), cloud CLIs (aws, docker), and virtualization tools (kvm, virsh) are now standard parts of the Linux admin toolkit, and this book treats them as first-class citizens.
【Reading Tips】
- **Use as a lookup, not a cover-to-cover read**: The book is structured alphabetically by command; skim the topic overview at the beginning to understand what's covered, then jump to specific commands as needed.
- **Deep-read the file system and LVM sections**: These are conceptually dense and benefit from sequential reading; understanding the PV/VG/LV model will save hours of troubleshooting later.
- **Pay attention to option tables**: For complex commands (rsync, find, iptables), the option lists are the most valuable part—scan them before attempting real tasks.
- **Cross-reference security tools**: SELinux and AppArmor commands are scattered; read them together to understand when to use which framework and how they interact with standard file permissions.
- **Skip the basics if you're experienced**: If you already know ls, cp, and grep, start at the process management or file system chapters to get the most value from your time.
【Coverage Limits】
The excerpts primarily cover the table of contents and command overview sections; detailed command syntax, examples, and option explanations are not included in this guide. Specific chapters on networking protocols, shell scripting, and graphical tools are only partially visible.
Passage locations
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23, 491 pages, paperback and e-book www.rheinwerk-computing.com/5650 Bernd Öggl, Michael Kofler Git: Project Management for Developers and DevOps Teams 2023,...
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yntax highlighting . . . . . . . . . . . . . . . . . . . . . 53 cat Outputs a file or combines multiple texts . . . . . . . . . . . . . . . . . . . . . . . 6...
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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 358 timeout Limits the execution time of a command . . . . . . . . . . . . . . . . . . . . . . ....
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XFS file system . . . . . . . . . . . . . . . . . . . . . . 414 xfs_repair Repairs a defective XFS file system . . . . . . . . . . . . . . . . . . . . . . ....
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