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	ls	list directory	, info	, #ls alternatives
	cat	concatenate files to stdout	cat(1), info	tac(1), #cat alternatives
	mkdir	make directory	, info
	rmdir	remove empty directory	, info
	rm	remove files or directories	, info	shred
	cp	copy files or directories	, info	#cp alternatives
	mv	move files or directories	, info
	ln	make hard or symbolic links	, info	(soname recovery)
	chown	change file owner and group	chown(1), info
	chmod	change file permissions	chmod(1), info
	dd	convert and copy a file	, info	#dd alternatives
	df	report file system disk space usage	, info	#df alternatives
	du	estimate disk space used by files and directories	, info	#du alternatives
GNU	tar	tar archiver	, info	archivers
GNU	less	terminal pager		terminal pagers
GNU findutils	find	search files or directories	, info, GregsWiki	#find alternatives
GNU	diff	compare files line by line	diff(1), info	#diff alternatives
GNU	grep	print lines matching a pattern	, info	#grep alternatives
GNU	sed	stream editor	, info, one-liners
GNU	awk	pattern scanning and processing language	, info	, mawk^AUR,
	dmesg	print or control the kernel ring buffer		systemd journal
	lsblk	list block devices
	mount	mount a filesystem	mount(8)
	umount	unmount a filesystem
	su	substitute user		sudo, doas
	kill	terminate a process		, killall(1)
	pgrep	look up processes by name or attributes
	ps	show information about processes		, task managers
	free	display amount of free and used memory		, task managers

Preventing data loss

rm, , and shell redirections happily delete or overwrite files without asking. rm, , and 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
	type	print the type of a command		, ,
	time	time a command
GNU	tee	read stdin and write to stdout and files	tee(1), info
	mktemp	make a temporary file or directory	, info
	mknod	create named pipe or device node	mknod(1), , info
	truncate	shrink or extend the size of a file	, info
	basenc	encoding input and output it	, , info
	cut	print selected parts of lines	, info	, hck,
	tr	translate or delete characters	, info
	od	dump files in octal and other formats	, info	, vim's
	sort	sort lines	sort(1), info
	uniq	report or omit repeated lines	, info	, , huniq-git^AUR
	comm	compare two sorted files line by line	, info
	head	output the first part of files	, info
	join	join lines of two inputs on a common field	, info
	md5sum	calculate cryptography hash functions of inputs and output	, , info	shasum(1), ,
	tail	output the last part of files, or follow files	tail(1), info
	wc	print newline, word and byte count	, info
GNU	strings	print printable characters in binary files	, info
	column	columnate file, optionally pretty-printing in table with grid		, csview^AUR
GNU findutils	xargs	combine or template arguments from stdin to invoke external command		parallel(1) ()
GNU	iconv	convert character encodings		,
GNU	uudecode	encode file into email friendly text	, , info	uudeview(1)
	file	guess file type

The package provides useful tools like 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

ubase — An extension of the sbase utilities.

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

cat alternatives

cd alternatives

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

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

find alternatives

plocate — A much faster locate.

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

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

diff alternatives

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

git diff can do a word diff with , using it can also be used for files outside of Git working trees.

grep alternatives

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 .

Interactive filters

peco — Simplistic interactive filtering tool.

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

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

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

dd alternatives

Alternative dd implementations

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

Spin-offs of GNU dd

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

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.

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

buffer spin-offs

This subsection lists forks of , 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.

df alternatives

du alternatives

dust — A more intuitive version of du, in rust.

https://github.com/bootandy/dust || dust

gollark: I don't want people to be able to claim random asteroids without visiting them.

gollark: Mostly because it doesn't seem very economically viable, because there is no spacey infrastructure.

gollark: But they don't.

gollark: If someone had valuable assets up there the legal issues would be worked out.

gollark: I don't think the issue is just the OST, though.