Editing Basic Linux Commands (section)

== <span id="commands"></span>Common Commands ==

=== Navigation & File Management ===
{| class="wikitable sortable"
! Command !! Description !! Usage
|-
| [[#ex-pwd|<code>pwd</code>]] || Print working directory || <code>pwd</code>
|-
| [[#ex-cd|<code>cd</code>]] || Change directory || <code>cd [DIRECTORY]</code>
|-
| [[#ex-ls|<code>ls</code>]] || List directory contents || <code>ls [OPTIONS] [FILE...]</code>
|-
| [[#ex-tree|<code>tree</code>]] || Recursively list directories as tree || <code>tree [DIRECTORY]</code>
|-
| [[#ex-mkdir|<code>mkdir</code>]] || Create directory || <code>mkdir [OPTIONS] DIRECTORY</code>
|-
| [[#ex-rmdir|<code>rmdir</code>]] || Remove empty directory || <code>rmdir DIRECTORY</code>
|-
| [[#ex-cp|<code>cp</code>]] || Copy files or directories || <code>cp SOURCE DEST</code>
|-
| [[#ex-mv|<code>mv</code>]] || Move or rename files/directories || <code>mv SOURCE DEST</code>
|-
| [[#ex-rm|<code>rm</code>]] || Delete files or directories || <code>rm [OPTIONS] FILE...</code>
|-
| [[#ex-touch|<code>touch</code>]] || Create empty file or update timestamp || <code>touch FILENAME</code>
|-
| [[#ex-ln|<code>ln</code>]] || Create hard or symbolic links || <code>ln [OPTIONS] TARGET LINK_NAME</code>
|-
| [[#ex-stat|<code>stat</code>]] || Display detailed file information || <code>stat FILE</code>
|-
| [[#ex-file|<code>file</code>]] || Detect file type || <code>file FILE</code>
|-
| [[#ex-basename|<code>basename</code>]] || Strip directory and suffix from filename || <code>basename PATH</code>
|-
| [[#ex-dirname|<code>dirname</code>]] || Extract directory part of file path || <code>dirname PATH</code>
|-
| [[#ex-find|<code>find</code>]] || Search for files and directories || <code>find [PATH] [OPTIONS] [EXPRESSION]</code>
|-
| [[#ex-locate|<code>locate</code>]] || Find files using database (faster than find) || <code>locate FILENAME</code>
|-
| [[#ex-chmod|<code>chmod</code>]] || Change file permissions || <code>chmod [OPTIONS] MODE FILE</code>
|-
| [[#ex-chown|<code>chown</code>]] || Change file ownership (user) || <code>chown [OPTIONS] USER FILE</code>
|-
| [[#ex-chgrp|<code>chgrp</code>]] || Change group ownership || <code>chgrp [OPTIONS] GROUP FILE</code>
|-
| [[#ex-umask|<code>umask</code>]] || Set default file permission mask || <code>umask [MASK]</code>
|-
| [[#ex-tar|<code>tar</code>]] || Archive files into tarball || <code>tar -czf ARCHIVE.tar.gz FILES</code>
|-
| [[#ex-gzip|<code>gzip</code>]] || Compress files using Gzip || <code>gzip FILE</code>
|-
| [[#ex-gunzip|<code>gunzip</code>]] || Decompress Gzip files || <code>gunzip FILE.gz</code>
|-
| [[#ex-zip|<code>zip</code>]] || Compress files into ZIP archive || <code>zip ARCHIVE.zip FILES</code>
|-
| [[#ex-unzip|<code>unzip</code>]] || Extract ZIP archive || <code>unzip ARCHIVE.zip</code>
|-
| [[#ex-dd|<code>dd</code>]] || Copy and convert data (low-level) || <code>dd if=SOURCE of=DEST bs=BLOCKSIZE</code>
|-
| [[#ex-mount|<code>mount</code>]] || Mount a filesystem || <code>mount [DEVICE] [MOUNTPOINT]</code>
|-
| [[#ex-umount|<code>umount</code>]] || Unmount a filesystem || <code>umount [MOUNTPOINT]</code>
|-
| [[#ex-namei|<code>namei</code>]] || Follow a file path, showing each component || <code>namei PATH</code>
|-
| [[#ex-readlink|<code>readlink</code>]] || Resolve symbolic link to actual path || <code>readlink FILE</code>
|-
| [[#ex-realpath|<code>realpath</code>]] || Print the resolved absolute file path || <code>realpath FILE</code>
|-
| [[#ex-mktemp|<code>mktemp</code>]] || Create a temporary file or directory || <code>mktemp [TEMPLATE]</code>

|}

=== Viewing & Text Processing ===
{| class="wikitable sortable"
! Command !! Description !! Usage
|-
| [[#ex-cat|<code>cat</code>]] || Concatenate & display files || <code>cat [OPTIONS] FILE...</code>
|-
| [[#ex-less|<code>less</code>]] || Paginate large files || <code>less FILE</code>
|-
| [[#ex-more|<code>more</code>]] || View file one page at a time || <code>more FILE</code>
|-
| [[#ex-head|<code>head</code>]] || Show first lines of a file || <code>head [OPTIONS] FILE</code>
|-
| [[#ex-tail|<code>tail</code>]] || Show last lines / follow file || <code>tail [OPTIONS] FILE</code>
|-
| [[#ex-grep|<code>grep</code>]] || Search for patterns || <code>grep [OPTIONS] PATTERN FILE</code>
|-
| [[#ex-awk|<code>awk</code>]] || Pattern scanning & processing language || <code>awk 'pattern { action }' FILE</code>
|-
| [[#ex-sed|<code>sed</code>]] || Stream editor for filtering & transforming text || <code>sed [OPTIONS] 'SCRIPT' FILE</code>
|-
| [[#ex-cut|<code>cut</code>]] || Remove sections from each line || <code>cut [OPTIONS] FILE</code>
|-
| [[#ex-tr|<code>tr</code>]] || Translate or delete characters || <code>tr SET1 SET2</code>
|-
| [[#ex-sort|<code>sort</code>]] || Sort lines of text files || <code>sort [OPTIONS] FILE</code>
|-
| [[#ex-uniq|<code>uniq</code>]] || Filter out repeated lines || <code>uniq [OPTIONS] FILE</code>
|-
| [[#ex-wc|<code>wc</code>]] || Count lines, words, bytes || <code>wc [OPTIONS] FILE</code>
|-
| [[#ex-nl|<code>nl</code>]] || Number lines of a file || <code>nl FILE</code>
|-
| [[#ex-diff|<code>diff</code>]] || Show differences between files || <code>diff FILE1 FILE2</code>
|-
| [[#ex-tee|<code>tee</code>]] || Read from stdin and write to file and stdout || <code>COMMAND | tee FILE</code>
|}

=== System & User Info ===
{| class="wikitable sortable"
! Command !! Description !! Usage
|-
| [[#ex-whoami|<code>whoami</code>]] || Show current user || <code>whoami</code>
|-
| [[#ex-id|<code>id</code>]] || Display user/group IDs || <code>id [USERNAME]</code>
|-
| [[#ex-df|<code>df</code>]] || Disk usage overview || <code>df [OPTIONS]</code>
|-
| [[#ex-du|<code>du</code>]] || Show disk usage for files/directories || <code>du [OPTIONS] [PATH]</code>
|-
| [[#ex-uptime|<code>uptime</code>]] || Show how long the system has been running || <code>uptime</code>
|-
| [[#ex-uname|<code>uname</code>]] || System information (kernel, OS, architecture) || <code>uname -a</code>
|-
| [[#ex-hostname|<code>hostname</code>]] || Show or set system hostname || <code>hostname</code>
|-
| [[#ex-date|<code>date</code>]] || Display or set system date/time || <code>date</code>
|-
| [[#ex-cal|<code>cal</code>]] || Display a calendar || <code>cal</code>
|-
| [[#ex-env|<code>env</code>]] || Show environment variables || <code>env</code>
|-
| [[#ex-set|<code>set</code>]] || Display shell variables and functions || <code>set</code>
|-
| [[#ex-history|<code>history</code>]] || List previously executed commands || <code>history</code>
|-
| [[#ex-ps|<code>ps</code>]] || Display running processes || <code>ps aux</code>
|-
| [[#ex-top|<code>top</code>]] || Real-time system process monitor || <code>top</code>
|-
| [[#ex-kill|<code>kill</code>]] || Terminate process by PID || <code>kill [-9] PID</code>
|-
| [[#ex-pkill|<code>pkill</code>]] || Kill processes by name || <code>pkill PROCESS_NAME</code>
|-
| [[#ex-pgrep|<code>pgrep</code>]] || Search for processes by name || <code>pgrep PROCESS_NAME</code>
|-
| [[#ex-w|<code>w</code>]] || Show who is logged in and what they are doing || <code>w</code>
|-
| [[#ex-who|<code>who</code>]] || Show who is logged in || <code>who</code>
|-
| [[#ex-last|<code>last</code>]] || Show login history || <code>last</code>
|-
| [[#ex-free|<code>free</code>]] || Show memory usage || <code>free -h</code>
|}

=== User & Group Management ===
{| class="wikitable sortable"
! Command !! Description !! Usage
|-
| [[#ex-useradd|<code>useradd</code>]] || Add new user || <code>useradd [OPTIONS] USERNAME</code>
|-
| [[#ex-usermod|<code>usermod</code>]] || Modify existing user || <code>usermod [OPTIONS] USERNAME</code>
|-
| [[#ex-userdel|<code>userdel</code>]] || Remove user || <code>userdel [OPTIONS] USERNAME</code>
|-
| [[#ex-groupadd|<code>groupadd</code>]] || Create new group || <code>groupadd GROUP</code>
|-
| [[#ex-groupdel|<code>groupdel</code>]] || Delete group || <code>groupdel GROUP</code>
|-
| [[#ex-passwd|<code>passwd</code>]] || Set/modify user password || <code>passwd USERNAME</code>
|}

=== Security & Permissions ===
{| class="wikitable sortable"
! Command !! Description !! Usage
|-
| [[#ex-sudo|<code>sudo</code>]] || Execute command as another user (root by default) || <code>sudo COMMAND</code>
|-
| [[#ex-su|<code>su</code>]] || Switch user context || <code>su [USER]</code>
|-
| [[#ex-setfacl|<code>setfacl</code>]] || Set POSIX ACL on files/directories || <code>setfacl -m u:USER:rwx FILE</code>
|-
| [[#ex-getfacl|<code>getfacl</code>]] || View POSIX ACL || <code>getfacl FILE</code>
|}

=== Process & Job Control ===
{| class="wikitable sortable"
! Command !! Description !! Usage
|-
| [[#ex-jobs|<code>jobs</code>]] || List background/paused jobs || <code>jobs -l</code>
|-
| [[#ex-bg|<code>bg</code>]] || Resume job in background || <code>bg %1</code>
|-
| [[#ex-fg|<code>fg</code>]] || Bring job to foreground || <code>fg %1</code>
|-
| [[#ex-nohup|<code>nohup</code>]] || Run command immune to hangup || <code>nohup COMMAND &</code>
|-
| [[#ex-disown|<code>disown</code>]] || Remove job from shell’s job table || <code>disown %1</code>
|-
| [[#ex-nice|<code>nice</code>]] || Start task with priority || <code>nice -n 10 COMMAND</code>
|-
| [[#ex-renice|<code>renice</code>]] || Change priority of running PID || <code>renice +5 PID</code>
|}

=== System Monitoring & Performance ===
{| class="wikitable sortable"
! Command !! Description !! Usage
|-
| [[#ex-htop|<code>htop</code>]] || Interactive process viewer || <code>htop</code>
|-
| [[#ex-vmstat|<code>vmstat</code>]] || Report virtual memory stats || <code>vmstat 1</code>
|-
| [[#ex-iostat|<code>iostat</code>]] || CPU & I/O statistics || <code>iostat -xz 1</code>
|-
| [[#ex-iotop|<code>iotop</code>]] || Real‑time I/O usage || <code>iotop</code>
|-
| [[#ex-dstat|<code>dstat</code>]] || Versatile resource stats || <code>dstat -tcm --top-io</code>
|}

=== Disk & Filesystem Management ===
{| class="wikitable sortable"
! Command !! Description !! Usage
|-
| [[#ex-lsblk|<code>lsblk</code>]] || List block devices || <code>lsblk -f</code>
|-
| [[#ex-blkid|<code>blkid</code>]] || Locate/print block device attributes || <code>blkid DEVICE</code>
|-
| [[#ex-fdisk|<code>fdisk</code>]] || Partition table editor (MBR) || <code>fdisk /dev/sda</code>
|-
| [[#ex-parted|<code>parted</code>]] || Partition tool (GPT/MBR) || <code>parted /dev/sda</code>
|-
| [[#ex-mkfs|<code>mkfs</code>]] || Create filesystem on device || <code>mkfs.ext4 /dev/sda1</code>
|-
| [[#ex-fsck|<code>fsck</code>]] || Check/repair filesystem || <code>fsck -f /dev/sda1</code>
|-
| [[#ex-tune2fs|<code>tune2fs</code>]] || Adjust ext2/3/4 filesystem params || <code>tune2fs -l /dev/sda1</code>
|}


=== Networking ===
{| class="wikitable sortable"
! Command !! Description !! Usage
|-
| [[#ex-ping|<code>ping</code>]] || Test network connectivity (ICMP) || <code>ping [OPTIONS] DESTINATION</code>
|-
| [[#ex-curl|<code>curl</code>]] || Retrieve data from URLs / APIs || <code>curl [OPTIONS] URL</code>
|-
| [[#ex-ssh|<code>ssh</code>]] || Secure remote shell & tunnelling || <code>ssh [OPTIONS] USER@HOST</code>
|}

=== Package & Software Management ===
{| class="wikitable sortable"
! Command !! Description !! Usage
|-
| [[#ex-apt|<code>apt</code>]] || Debian/Ubuntu package tool || <code>apt update && apt upgrade</code>
|-
| [[#ex-dnf|<code>dnf</code>]] || Fedora/RHEL package manager || <code>dnf install PACKAGE</code>
|-
| [[#ex-yum|<code>yum</code>]] || Legacy RHEL/CentOS package tool || <code>yum remove PACKAGE</code>
|-
| [[#ex-pacman|<code>pacman</code>]] || Arch Linux package manager || <code>pacman -Syu</code>
|-
| [[#ex-dpkg|<code>dpkg</code>]] || Debian low‑level package tool || <code>dpkg -i PACKAGE.deb</code>
|-
| [[#ex-rpm|<code>rpm</code>]] || RPM low‑level package tool || <code>rpm -q PACKAGE</code>
|-
| [[#ex-snap|<code>snap</code>]] || Universal package system || <code>snap install APP</code>
|-
| [[#ex-flatpak|<code>flatpak</code>]] || Sandboxed app manager || <code>flatpak install REMOTE APP</code>
|}

=== Scripting & Automation ===
{| class="wikitable sortable"
! Command !! Description !! Usage
|-
| [[#ex-bash|<code>bash</code>]] || GNU Bourne‑Again Shell || <code>#!/usr/bin/env bash</code>
|-
| [[#ex-sh|<code>sh</code>]] || POSIX shell || <code>sh SCRIPT.sh</code>
|-
| [[#ex-crontab|<code>crontab</code>]] || Schedule recurring jobs || <code>crontab -e</code>
|-
| [[#ex-at|<code>at</code>]] || Schedule one‑time tasks || <code>echo "script.sh" | at 02:00</code>
|-
| [[#ex-alias|<code>alias</code>]] || Create command shortcuts || <code>alias ll='ls -alh'</code>
|-
| [[#ex-export|<code>export</code>]] || Set environment variables || <code>export PATH=$PATH:/custom/bin</code>
|}


=== Help & Documentation ===
{| class="wikitable sortable"
! Command !! Description !! Usage
|-
| [[#ex-man|<code>man</code>]] || Read manual pages || <code>man COMMAND</code>
|-
| [[#ex-echo|<code>echo</code>]] || Display text / variables || <code>echo [STRING]</code>
|}

|}