Core utilities

Core utilities are the basic, fundamental tools of a GNU/Linux system. This article provides an incomplete overview of them, links their documentation and describes useful alternatives. The scope of this article includes, but is not limited to, the GNU coreutils. Most core utilities are traditional Unix tools and many were standardized by POSIX but have been developed further to provide more features.

Most command-line interfaces are documented in man pages, utilities by the GNU Project are documented primarily in Info manuals, some shells provide a help command for shell builtin commands. Additionally most utilities print their usage when run with the --help flag.

Essentials

The following table lists some important utilities which Arch Linux users should be familiar with. See also intro(1).

Package	Utility	Description	Documentation	Alternatives
shell built-ins	cd	change directory	cd(1p)	#cd alternatives
GNU coreutils	ls	list directory	ls(1), info	tree, #ls alternatives
	cat	concatenate files to stdout	cat(1), info	tac(1), #cat alternatives
	mkdir	make directory	mkdir(1), info
	rmdir	remove empty directory	rmdir(1), info
	rm	remove files or directories	rm(1), info	shred unlink(1)
	cp	copy files or directories	cp(1), info	#cp alternatives
	mv	move files or directories	mv(1), info
	ln	make hard or symbolic links	ln(1), info	sln(8) (soname recovery)
	chown	change file owner and group	chown(1), info	chgrp(1)
	chmod	change file permissions	chmod(1), info
	dd	convert and copy a file	dd(1), info	#dd alternatives
	df	report file system disk space usage	df(1), info	#df alternatives
	du	estimate disk space used by files and directories	du(1), info	#du alternatives
GNU tar	tar	tar archiver	tar(1), info	archivers
GNU less	less	terminal pager	less(1)	terminal pagers
GNU findutils	find	search files or directories	find(1), info, GregsWiki	#find alternatives
GNU diffutils	diff	compare files line by line	diff(1), info	#diff alternatives
GNU grep	grep	print lines matching a pattern	grep(1), info	#grep alternatives
GNU sed	sed	stream editor	sed(1), info, one-liners	sad, sd
GNU AWK (gawk)	AWK	pattern scanning and processing language	gawk(1), info	AWK#Alternative implementations
util-linux	dmesg	print or control the kernel ring buffer	dmesg(1)	systemd journal
	lsblk	list block devices	lsblk(8)
	mount	mount a filesystem	mount(8)
	umount	unmount a filesystem	umount(8)
	su	substitute user	su(1)	sudo, doas
	kill	terminate a process	kill(1)	pkill(1), killall(1)
procps-ng	pgrep	look up processes by name or attributes	pgrep(1)	pidof(1)
	ps	show information about processes	ps(1)	top(1), system monitors
	free	display amount of free and used memory	free(1)	top(1), system monitors

Preventing data loss

rm, mv, cp and shell redirections happily delete or overwrite files without asking. rm, mv, and cp all support the -i flag to prompt the user before every removal / overwrite. Some users like to enable the -i flag by default using aliases. Relying upon these shell options can be dangerous, because you get used to them, resulting in potential data loss when you use another system or user that does not have them. The best way to prevent data loss is to create backups.

Nonessentials

This table lists core utilities that often come in handy.

Package	Utility	Description	Documentation	Alternatives
shell built-ins	alias	define or display aliases	alias(1p)
	type	print the type of a command	type(1p)	command(1p), whereis(1), which(1)
	time	time a command	time(1p)
GNU coreutils	tee	read stdin and write to stdout and files	tee(1), info	pee(1)
	mktemp	make a temporary file or directory	mktemp(1), info
	mknod	create named pipe or device node	mknod(1), mkfifo(1), info
	truncate	shrink or extend the size of a file	truncate(1), info	fallocate(1)
	basenc	encoding input and output it	basenc(1), base64(1), info
	cut	print selected parts of lines	cut(1), info	colrm(1), hck, choose
	tr	translate or delete characters	tr(1), info	uconv(1)
	od	dump files in octal and other formats	od(1), info	hexdump(1), vim's xxd(1)
	sort	sort lines	sort(1), info
	uniq	report or omit repeated lines	uniq(1), info	anewer, runiq^AUR, huniq-git^AUR
	comm	compare two sorted files line by line	comm(1), info	zet^AUR
	head	output the first part of files	head(1), info
	join	join lines of two inputs on a common field	join(1), info	combine(1) zet^AUR
	md5sum	calculate cryptography hash functions of inputs and output	sha256sum(1), sha512sum(1), info	shasum(1), hashdeep(1)^{[dead link 2024-10-12]}, rhash(1)
	tail	output the last part of files, or follow files	tail(1), info
	wc	print newline, word and byte count	wc(1), info
GNU binutils	strings	print printable characters in binary files	strings(1), info	stringsext^AUR
util-linux	column	columnate file, optionally pretty-printing in table with grid	column(1)	paste(1), csview^AUR
GNU findutils	xargs	combine or template arguments from stdin to invoke external command	xargs(1)	parallel(1) (parallel_alternatives(7))
GNU glibc	iconv	convert character encodings	iconv(1)	recode, uconv(1)
GNU sharutils	uudecode	encode file into email friendly text	uuencode(1), uudecode(1), info	uudeview(1)
file	file	guess file type	file(1)

The moreutils package provides useful tools like sponge(1) that are missing from the GNU coreutils.

Alternatives

Alternative core utilities are provided by the following packages:

BusyBox — Utilities for rescue and embedded systems.

https://busybox.net || busybox

Toybox — An all-in-one Linux command line.

https://landley.net/toybox || toybox^AUR

uutils — Cross-platform Rust rewrite of the GNU coreutils.

https://github.com/uutils/coreutils || uutils-coreutils

Heirloom Toolchest — Traditional implementations of standard Unix utilities.

https://heirloom.sourceforge.net || heirloom-sh^AUR, heirloom-doctools^AUR

9base — A port of various original Plan9 tools to unix.

https://tools.suckless.org/9base || 9base

sbase — A suckless variant of the *nix core utilities.

https://core.suckless.org/sbase || sbase-git^AUR

ubase — An extension of the sbase utilities.

https://core.suckless.org/ubase || ubase-git^AUR

cat alternatives

bat — A cat clone with syntax highlighting and Git integration.

https://github.com/sharkdp/bat || bat

cd alternatives

zoxide — A smart cd command that learns your habits, allowing you to navigate anywhere in just a few keystrokes.

https://github.com/ajeetdsouza/zoxide || zoxide

autojump — A faster way to navigate your filesystem from the command line.

https://github.com/wting/autojump || autojump^AUR

date alternatives

This article or section is a candidate for moving to List of applications/Other.

Notes: These are not alternatives, date is not even mentioned on this page. (Discuss in Talk:Core utilities)

dateutils — Nifty command line date and time utilities; fast date calculations and conversion in the shell.

https://www.fresse.org/dateutils/ || dateutils

pdd — Tiny datetime diff calculator.

https://github.com/jarun/pdd || pdd^AUR

cp alternatives

Using rsync#As cp/mv alternative allows you to resume a failed transfer, to show the transfer status, to skip already existing files and to make sure of the destination files integrity using checksums.

ls alternatives

broot — A new way to see and navigate directory trees.

https://github.com/Canop/broot || broot

clifm — A file manager that can list files like ls(1) would (plus icons and RGB colors support).

https://github.com/leo-arch/clifm/wiki/Advanced#files-lister-ls-mode || clifm^AUR

eza — Another ls replacement with color support, tree view, git integration and other features. Based on exa, which is no longer supported.

https://github.com/eza-community/eza || eza

lsd — Modern ls with a lot of pretty colors and awesome icons.

https://github.com/Peltoche/lsd || lsd

find alternatives

fd — Simple, fast and user-friendly alternative to find. Ignores hidden and .gitignore'd files by default.

https://github.com/sharkdp/fd || fd

fuzzy-find — Fuzzy completion for finding files.

https://github.com/silentbicycle/ff || ff-git^AUR

plocate — A much faster locate.

https://plocate.sesse.net/ || plocate

rawhide — find files using pretty C expressions.

https://raf.org/rawhide/ || rawhide^AUR

For graphical file searchers, see List of applications/Utilities#File searching.

diff alternatives

While diffutils does not provide a word-wise diff, several other programs do:

git diff can do a word diff with --color-words, using --no-index it can also be used for files outside of Git working trees.
cwdiff — A GNU wdiff wrapper that colorizes the output.

https://github.com/junghans/cwdiff || cwdiff^AUR

git-delta — A syntax-highlighting pager for git, diff, and grep output.

https://dandavison.github.io/delta/ || git-delta

dwdiff — A word diff front-end for the diff program; supports colors.

https://os.ghalkes.nl/dwdiff.html || dwdiff^AUR

icdiff — A colorized diff tool written in Python. "Improved color diff" is meant to supplement normal diff use.

https://github.com/jeffkaufman/icdiff || icdiff^AUR

wdiff — A wordwise implementation of GNU diff; does not support colors.

https://www.gnu.org/software/wdiff/ || wdiff

grep alternatives

mgrep — A multiline grep.

https://sourceforge.net/projects/multiline-grep/ || mgrep^AUR

pdfgrep — A tool to search text in PDF files.

https://pdfgrep.org/ || pdfgrep

ripgrep-all — Search in plain text and also in PDFs, E-Books, Office documents, zip, tar.gz.

https://github.com/phiresky/ripgrep-all || ripgrep-all

Code searchers

These tools aim to replace grep for code search. They do recursive search by default, skip binary files and respect .gitignore.

ack — A Perl-based grep replacement, aimed at programmers with large trees of heterogeneous source code.

https://beyondgrep.com/ || ack

ripgrep (rg) — A search tool that combines the usability of ag with the raw speed of grep.

https://github.com/BurntSushi/ripgrep || ripgrep

The Silver Searcher (ag) — Code searching tool similar to ack, but faster.

https://github.com/ggreer/the_silver_searcher || the_silver_searcher

ugrep (ug) — Ultrafast grep with interactive user interface, fuzzy search, boolean queries, hexdumps and more.

https://github.com/Genivia/ugrep || ugrep

Interactive filters

fzf — General-purpose command-line fuzzy finder, powered by find by default.

https://github.com/junegunn/fzf || fzf

fzy — A fast, simple fuzzy text selector with an advanced scoring algorithm.

https://github.com/jhawthorn/fzy || fzy

peco — Simplistic interactive filtering tool.

https://github.com/peco/peco || peco

percol — Adds flavor of interactive filtering to the traditional pipe concept of the UNIX shell.

https://github.com/mooz/percol || percol^AUR

skim — Fuzzy finder written in Rust, similar to fzf.

https://github.com/lotabout/skim || skim

dd alternatives

This article or section needs expansion.

Reason: ddrescue should be added to a list below and briefly described. Given the name similarity, it would be nice to mention the differences from dd_rescue. (Discuss in Talk:Core utilities)

Alternative dd implementations

This subsection lists dd implementations whose interface and default behaviour is mostly compliant with the POSIX specification of dd(1p).

ddpt — A portable rewrite of sg_dd(8) by the SCSI subsystem maintainer of the Linux kernel, with optional but very specialised hardware I/O (SCSI command sets) support, plus many other features.

https://sg.danny.cz/sg/ddpt.html || ddpt^AUR

sdd — A dd implementation portable across UNIX environments by Joerg Schilling, that can checksum the copied data and retry reading bad blocks.

https://schilytools.sourceforge.net/ || schily-tools-sdd^AUR

Spin-offs of GNU dd

The GNU implementation of dd found in coreutils also conforms to POSIX. This subsection lists its forks.

dcfldd — feature-enhanced fork of GNU dd for forensics and security scenarios, includes on-the-fly hashing capability, flexible wipes, write verification, output to multiple targets at the same time, split and piped output.

https://dcfldd.sourceforge.net || dcfldd^AUR

dc3dd — Another patched version of GNU dd from the United States Department of Defense Cyber Crime Center (DC3), with similar goals and features to dcfldd.

https://sourceforge.net/projects/dc3dd/ || dc3dd^AUR

Modernised dd analogues

This subsection lists dd alternatives that do not conform to POSIX (in terms of the JCL-resembling command-line syntax and default behaviour).

dd_rescue — A feature-packed, modernised dd analogue that is suitable for daily scripting, disk cloning, and data recovery.

https://www.garloff.de/kurt/linux/ddrescue/ || dd_rescue

rw — Minimal and portable dd analogue with conventional command-line flags.

https://sortix.org/rw/ || rw^AUR

buffer spin-offs

This subsection lists forks of buffer^AUR, a general-purpose I/O buffering utility similar to dd but has a dynamic-sized buffer. It supports blockwise I/O and can be used when dumping from/to an LTO-tape to avoid shoe shining.