Essential Linux Command Cheat Sheet: Decode Common Abbreviations

pwd: print working directory – displays the absolute path of the current directory.

ps: process status – shows information about running processes (similar to Windows Task Manager). Common option: -auxf.

df: disk free – reports available disk space and filesystem information.

du: disk usage – shows the amount of space used by files and directories.

rpm: Red Hat Package Management – package manager for Red Hat based systems.

rmdir: remove directory – deletes an empty directory.

rm: remove – deletes files or directories.

cat: concatenate – displays file contents; can combine files (e.g., cat file1 file2 >> file3).

insmod: install module – loads a kernel module.

ln -s: link – creates a symbolic (soft) link.

mkdir: make directory – creates a new directory.

touch: creates an empty file or updates a file's timestamp.

man: manual – displays the manual page for a command.

su: switch user – changes the current user identity.

cd: change directory – navigates to a different directory.

ls: list files – lists directory contents.

mkfs: make filesystem – creates a new filesystem.

fsck: filesystem check – checks and repairs a filesystem.

uname: Unix name – prints system information.

lsmod: list modules – shows loaded kernel modules.

mv: move – moves or renames files.

cp: copy – copies files.

ln: link – creates a hard link.

fg: foreground – brings a background job to the foreground.

bg: background – resumes a stopped job in the background.

chown: change owner – changes file ownership.

chgrp: change group – changes a file's group.

chmod: change mode – modifies file permissions.

umount: unmount – detaches a mounted filesystem.

dd: disk dump – copies and converts raw data.

tar: tape archive – creates or extracts archive files.

ldd: list dynamic dependencies – shows shared library dependencies of executables.

rmmod: remove module – unloads a kernel module.

rc files (e.g., .bashrc, .xinitrc): resource configuration scripts.

Knnxxx / Snnxxx (in rc?.d): K = Kill, S = Service, followed by a numeric order and service identifier.

.a: archive – static library file.

.so: shared object – dynamically linked library.

.o: object file – compiled result of a C/C++ source file.

RPM: Red Hat Package Manager.

dpkg: Debian package manager.

apt: advanced package tool – package manager for Debian-based distributions.

bin: binaries – executable files.

/dev: devices – device files.

/etc: etcetera – configuration files.

/lib: library – shared libraries.

/proc: processes – process information.

/sbin: superuser binaries – system administration executables.

/tmp: temporary – temporary files.

/usr: Unix shared resources – user utilities and libraries.

/var: variable – variable data files.

FIFO: first in, first out – named pipe.

GRUB: GRand Unified Bootloader.

IFS: internal field separators – defines word boundaries for the shell.

LILO: LInux LOader.

MySQL: named after the founder’s daughter.

SQL: structured query language.

PHP: personal home page tools – originally "PHP Hypertext Preprocessor".

Perl: practical extraction and report language (humorously "pathologically eclectic rubbish lister").

Python: named after the Monty Python comedy series.

Tcl: tool command language.

Tk: toolkit.

VT: video terminal.

YaST: Yet Another Setup Tool.

Apache: "a patchy" server.

ar: archiver.

as: assembler.

awk: Aho, Weinberger, Kernighan – named after the authors' initials.

bash: Bourne Again SHell.

bc: basic (better) calculator.

biff: named after the author's dog.

cal: calendar.

chmod, chown, chgrp, chsh, etc.: various file attribute modifiers.

cmp: compare files.

cobol: common object request broker architecture.

comm: common – compare two sorted files.

cpio: copy in and out – archive utility.

cpp: C preprocessor.

cron: Chronos – time‑based job scheduler.

cvs: concurrent versions system.

daemon: disk and execution monitor.

dc: desk calculator.

diff: difference – compares files line by line.

dmesg: diagnostic message – kernel ring buffer output.

ed: editor.

egrep: extended grep.

elf: extensible linking format.

emacs: editor macros.

eval: evaluate – executes arguments as a command.

exec: execute a program.

fd: file descriptors.

fgrep: fixed grep.

fmt: format – simple text formatter.

fsck: file system check.

fstab: filesystem table – static information about filesystems.

gawk: GNU awk.

gpg: GNU privacy guard.

groff: GNU troff.

hal: hardware abstraction layer.

joe: Joe's own editor.

ksh: Korn SHell.

lame: LAME – MP3 encoder.

lex: lexical analyser.

lisp: list processing – humorously "lots of irritating superfluous parentheses".

ln: link – creates hard or symbolic links.

lpr: line printer.

lsof: list open files.

m4: macro processor version 4.

mawk: Mike Brennan's awk.

mc: Midnight Commander.

mkfs: make filesystem.

mknod: make node – creates device files.

motd: message of the day.

mozilla: MOsaic GodZilla (historical name).

mtab: mount table.

nano: Nano's ANOther editor.

nawk: new awk.

nl: number of lines.

nm: names – lists symbols from object files.

nohup: no hangup – runs a command immune to hangups.

nroff: new roff – text formatting.

od: octal dump – displays file contents in various formats.

passwd: password file – changes user passwords.

pg: pager – displays text one screen at a time.

pico: Pine's message composition editor.

pine: program for internet news & email – "Pine is not Elm".

ping: packet internet grouper – network reachability test.

popd: pop directory – returns to previous directory.

pr: pre‑format – prepares files for printing.

printf: print formatted – formatted output.

ps: process status – shows process information.

pty: pseudo tty – terminal emulation.

pushd: push directory – saves current directory and changes to another.

rc: runcom – run command scripts (also Plan 9 shell).

rev: reverse – reverses lines of text.

rm: remove – deletes files or directories.

rn: read news – reads Usenet news.

roff: run off – text formatting.

rpm: RPM package manager – Red Hat package manager.

rsh, rlogin, rvim: remote shell, remote login, remote vim.

rxvt: X terminal emulator.

sed: stream editor – performs basic text transformations.

seq: sequence – generates sequences of numbers.

shar: shell archive – creates a self‑extracting archive.

slrn: S‑Lang rn – newsreader.

ssh: secure shell – encrypted remote login.

ssl: secure sockets layer – cryptographic protocol.

stty: set tty – changes and prints terminal line settings.

su: substitute user – switch user identity.

svn: subversion – version control system.

tar: tape archive – archive utility.

tcsh: TENEX C shell – enhanced C shell.

tee: T – reads from standard input and writes to standard output and files.

telnet: terminal emulation over network – unencrypted remote login.

termcap: terminal capability database.

terminfo: terminal information database.

tex: TeX – typesetting system.

tr: translate – transliterates characters.

troff: typesetter new roff – document formatting.

tsort: topological sort – orders directed graphs.

tty: teletypewriter – terminal device.

twm: Tom's window manager.

tz: timezone.

udev: userspace dev – device manager for the Linux kernel.

ulimit: user limit – controls resources available to the shell.

umask: user mask – default file permission mask.

uniq: unique – filters adjacent duplicate lines.

vim: vi improved – powerful text editor.

wall: write all – sends a message to all logged‑in users.

wc: word count – counts lines, words, and bytes.

wine: "WINE Is Not an Emulator" – runs Windows applications on Linux.

xargs: extended arguments – builds and executes command lines from standard input.

xdm: X display manager – graphical login manager.

xlfd: X logical font description – font naming scheme.

xmms: X multimedia system – audio player.

xrdb: X resources database – manages X server resources.

xwd: X window dump – captures screen images.

yacc: yet another compiler compiler – parser generator.

Fish: friendly interactive shell – user‑friendly command line.

MIME: multipurpose internet mail extensions.

ECMA: European Computer Manufacturers Association.