basename strips directory and suffixes from filenames. cat concatenates file(s) or standard input to standard output. chgrp changes the group ownership of each given file to the named group, which can be either a group name or a numeric group ID. chmod changes the permissions of each given file according to mode, which can be either a symbolic representation of changes to make or an octal number representing the bit pattern for the new permissions. chown changes the user and/or group ownership of each given file. chroot runs a command or interactive shell with special root directory. cksum prints CRC checksum and byte counts of each specified file. comm compares two sorted files line by line. cp copies files from one place to another. csplit outputs pieces of a file separated by (a) pattern(s) to files xx01, xx02, ..., and outputs byte counts of each piece to standard output. cut prints selected parts of lines from specified files to standard output. date displays the current time in a specified format, or sets the system date. dd copies a file (from the standard input to the standard output, by default) with a user-selectable blocksize, while optionally performing conversions on it. df displays the amount of disk space available on the filesystem containing each file name argument. If no file name is given, the space available on all currently mounted filesystems is shown. dir and vdir are versions of ls with different default output formats. These programs list each given file or directory name. Directory contents are sorted alphabetically. For ls, files are, by default, listed in columns sorted vertically if the standard output is a terminal; otherwise they are listed one per line. For dir, files are, by default, listed in columns sorted vertically. For vdir, files are, by default, listed in long format. dircolors outputs commands to set the LS_COLOR environment variable. The LS_COLOR variable is use to change the default color scheme used by ls and related utilities. dirname strips non-directory suffixes from file name. du displays the amount of disk space used by each file or directory listed on the command-line and by each of their subdirectories. echo displays a line of text. env runs a program in a modified environment. expand converts tabs in files to spaces, writing to standard output. expr evaluates expressions. factor prints the prime factors of all specified integer numbers. false always exits with a status code indicating failure. fmt reformats each paragraph in the specified file(s), writing to standard output. fold wraps input lines in each specified file (standard input by default), writing to standard output. groups prints a user's group memberships. head prints the first xx (10 by default) lines of each specified file to standard output. hostid prints the numeric identifier (in hexadecimal) for the current host. hostname reports or sets the name of the current host. id prints the effective user and group IDs of the current user or a given user. install copies files and sets their permission modes and, if possible, their owner and group. join joins lines of two files on a common field. kill terminates the given process. ln makes hard or soft (symbolic) links between files. logname prints the current user's login name. md5sum prints or checks MD5 checksums. mkdir creates directories with a given name. mkfifo creates a FIFO with each given name. mknod creates a FIFO, character special file or block special file with the given file name. mv moves files from one directory to another or renames files, depending on the arguments given to mv. nice runs a program with modified scheduling priority. nl writes each specified file to standard output, with line numbers added. nohup runs a command immune to hangups, with output to a log file. od writes an unambiguous representation, octal bytes by default, of a specified file to standard output. paste writes lines consisting of the sequentially corresponding lines from each specified file, separated by TABs, to standard output. pathchk checks whether file names are valid or portable. pinky is a lightweight finger utility which retrieves information about a certain user. pr paginates or columnates files for printing. printenv prints all or part of the environment. printf formats and prints data (the same as the C printf function). ptx produces a permuted index of file contents. pwd prints the name of the current/working directory. rm removes files or directories. rmdir removes directories, if they are empty. seq prints numbers in a certain range with a certain increment. sha1sum prints or checks 160-bit SHA1checksums. shred deletes a file securely, overwriting it first so that its contents can't be recovered. sleep delays for a specified amount of time. sort writes sorted concatenation of files to standard output. split outputs fixed-size pieces of an input file to PREFIXaa, PREFIXab, ... stty changes and prints terminal line settings. su runs a shell with substitute user and group IDs. sum prints checksum and block counts for each specified file. sync forces changed blocks to disk and updates the super block. tac writes each specified file to standard output, last line first. tail print the last xx (10 by default) lines of each specified file to standard output. tee reads from standard input and writes to standard output and files. test checks file types and compares values. touch changes the access and modification times of each given file to the current time. Files that do not exist are created empty. tr translates, squeezes, and/or deletes characters from standard input, writing to standard output. true always exits with a status code indicating success. tsort writes totally ordered lists consistent with the partial ordering in specified files. tty prints the file name of the terminal connected to standard input. uname prints system information. unexpand converts spaces in each file to tabs, writing to standard output. uniq removes duplicate lines from a sorted file. uptime tells how long the system has been running. users prints the user names of users currently logged in to the current host. wc prints line, word and byte counts for each specified file and a total line, if more than one file is specified. who shows who is logged on. whoami prints the user name associated with the current effective user ID. yes outputs 'y' or a given string repeatedly, until killed.