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 (see Heirloom) 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), bat | |
| mkdir | make directory | mkdir(1), info | ||
| rmdir | remove empty directory | rmdir(1), info | ||
| rm | remove files or directories | rm(1), info | shred | |
| 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 | ||
| 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 | ||
| df | report file system disk space usage | df(1), info | ||
| 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 | |
| GNU gawk | awk | pattern scanning and processing language | gawk(1), info | nawk, mawkAUR |
| 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, opendoas | |
| 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), htop | |
| free | display amount of free and used memory | free(1) |
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) | which(1) | |
| time | time a command | time(1p) | ||
| GNU coreutils | tee | read stdin and write to stdout and files | tee(1), info | |
| mktemp | make a temporary file or directory | mktemp(1), info | ||
| cut | print selected parts of lines | cut(1), info | ||
| tr | translate or delete characters | tr(1), info | ||
| 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 | ||
| comm | compare two sorted files line by line | comm(1), info | ||
| head | output the first part of files | head(1), info | ||
| 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 | stringsextAUR |
| GNU glibc | iconv | convert character encodings | iconv(1) | recode |
| 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 BusyBox, the Heirloom Toolchest, 9base, sbase-gitAUR and ubase-gitAUR.
cd alternatives
- zoxide — A smart cd command that learns your habits, allowing you to navigate anywhere in just a few keystrokes.
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.
- exa — Another ls replacement with color support, tree view, git integration and other features.
- lsd — Modern ls with a lot of pretty colors and awesome icons.
find alternatives
-
fd — Simple, fast and user-friendly alternative to find. Ignores hidden and
.gitignore'd files by default.
- fuzzy-find — Fuzzy completion for finding files.
- mlocate — Merging locate/updatedb implementation.
- plocate — A much faster locate.
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-indexit can also be used for files outside of Git working trees. - dwdiff — A word diff front-end for the diff program; supports colors.
- GNU wdiff — A wordwise implementation of GNU diff; does not support colors.
- cwdiff — A GNU wdiff wrapper that colorizes the output.
- icdiff — A colorized diff tool written in Python. "Improved color diff" is meant to supplement normal diff use.
See also List of applications/Utilities#Comparison, diff, merge.
grep alternatives
- mgrep — A multiline grep.
- pdfgrep — A tool to search text in PDF files.
- ripgrep-all — Search in plain text and also in PDFs, E-Books, Office documents, zip, tar.gz.
Code searchers
The following three 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.
- ripgrep (rg) — A search tool that combines the usability of ag with the raw speed of grep.
- The Silver Searcher (ag) — Code searching tool similar to Ack, but faster.
Interactive filters
- fzf — General-purpose command-line fuzzy finder, powered by find by default.
- fzy — A fast, simple fuzzy text selector with an advanced scoring algorithm.
- peco — Simplistic interactive filtering tool.
- percol — Adds flavor of interactive filtering to the traditional pipe concept of the UNIX shell.
- skim — Fuzzy finder written in Rust, similar to fzf.