Coreutils
The GNU Core Utilities is a package of GNU software containing the basic tools for Unix-like operating systems.
File utilities
chcon
changes file security context (SELinux);
changes file group ownership;
changes file ownership;
changes the permissions of a file or directory;
copies a file or directory;
copies and converts a file;
shows disk free space on filesystems;
dir
is exactly like ls -C -b
(files are
by default listed in columns and sorted vertically);
dircolors
setup color for ls
;
install
copies files and sets attributes;
creates a link to a file;
lists directory contents;
creates a directory;
mkfifo
makes named pipes (FIFOs);
makes block or character special files;
creates a temporary file or directory;
moves or renames files;
removes (deletes) files;
removes empty directories;
shred
overwrites a file to hide its contents, and optionally deletes it (may be not effective in some cases or with some filesystems, e.g., ext3, ext4, btrfs, reiser, xfs, ...);
sync
flushes file system buffers;
changes file's timestamps;
truncate
shrinks or extends the size of a file to the specifed size;
vdir
is exactly like ls -l -b
(files are
by default listed in long format);
Text utilities
base64 encode/decode data and print to standard output;
concatenates and prints files on the stdout;
checksums and count the bytes in a file;
compares two sorted files line by line;
csplit
splits a file into sections determined by context lines;
cut
removes sections from each line of files;
converts tabs to spaces;
fmt
simple optimal text formatter;
fold
wraps each input line to fit in specified width;
outputs the first 10 lines of a file to stdout;
join
joins lines of two files on a common field;
md5sum
computes and checks MD5 message digest;
nl
numbers lines of files;
dumps files in octal and other formats;
paste
merges lines of files;
ptx
produces a permuted index of file contents;
pr
converts text files for printing;
sha1sum
sha224sum
sha256sum
sha384sum
sha512sum
computes and checks SHA-1, SHA-224, SHA-256, SHA-384, SHA-512 message digest;
shuf
generates random permutations;
sorts lines of text files;
splits a file into pieces;
sum
checksums and counts the blocks in a file;
tac
concatenates and prints files in reverse;
outputs the last 10 lines of a file;
tr
translates or deletes characters;
tsort
performs a topological sort;
converts spaces to tabs;
removes duplicate lines from a sorted file;
prints the number of bytes, words, and lines in a file;
Shell utilities
arch
prints machine hardware name (like uname -m
);
basename
strips path prefix (directory) and suffix from filenames;
chroot
changes the root dir (i.e., allows to run cmd or interactive shell with special root dir);
prints/sets the system date and time;
dirname
strips last component (non-directory suffix) from the file name;
shows disk space usage on file systems;
echo
displays a specified line of text;
displays and modifies environment variables;
expr
evaluates expressions;
factor
factors numbers (e.g., factor 20
gives 2 2 5);
false
does nothing, but exits unsuccessfully (C lang defines EXIT_SUCCESS = 0, EXIT_FAILURE = 1);
groups
prints the groups of which the user is a member;
hostid
prints the numeric identifier for the current host (HEX);
prints real/effective UID and GID;
link
creates a link to a file;
logname
prints the user's login name;
modifies the scheduling priority;
nohup
allows a cmd to continue running after logging out;
pathchk
checks whether file names are valid or portable;
pinky
a lightweight version of finger
;
printenv
prints environment variables (e.g., printenv PATH
);
formats and prints data;
pwd
prints the current working directory;
readlink
displays value of a symbolic link;
runcon
run cmd with the specified security context;
seq
prints a sequence of numbers;
delays for a specified amount of time;
returns data about an inode;
stty
changes and prints terminal line settings;
runs a shell or cmd with substitute user and group IDs;
sends output to multiple files;
test
evaluates an expression;
timeout
runs cmd with a time limit;
true
does nothing, but exits successfully (EXIT_SUCCESS = 0);
tty
prints terminal name;
prints misc system information;
unlink
removes the specified file using the unlink
function (e.g., unlink msg2.txt
);
uptime
tells how long the system has been running;
users
prints the user names of users currently logged in to the current host;
prints a list of all users currently logged in;
whoami
prints the effective userid;
outputs a string repeatedly until killed by CTRL+C;