Command
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Description
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adduser
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Add a new user
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Print machine architecture
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awk
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Find and Replace text within file(s)
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bc
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An arbitrary precision calculator language
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Display a calendar
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Concatenate files and print on the standard output
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Change working directory
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Change the group ownership of files
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chkconfig
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Tool for maintaining the /etc/rc[0-6].d directory hierarchy
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chmod
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Change the access permissions of files and directories
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Change the user and group ownership of files
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chroot
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Change root directory
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cksum
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Print CRC checksum and byte counts
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clear
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Clear terminal screen
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cmp
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Compare two files
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comm
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Compare two sorted files line by line
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cp
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Copy one or more files to another location
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cron
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Daemon to execute scheduled commands
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crontab
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Schedule a command to run at a later time
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csplit
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Split a file into context-determined pieces
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cut
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Divide a file into several parts
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date
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Display or change the date & time
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dc
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Desk Calculator
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dd
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Data Dump – Convert and copy a file
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df
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Display free disk space
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diff
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Display the differences between two files
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diff3
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Show differences among three files
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dir
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Briefly list directory contents
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dircolors
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Colour setup for `ls’
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dirname
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Convert a full pathname to just a path
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du
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Estimate file space usage
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echo
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Display message on screen
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ed
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A line-oriented text editor (edlin)
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egrep
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Search file(s) for lines that match an extended expression
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eject
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Eject CD-ROM
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env
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Display, set, or remove environment variables
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expand
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Convert tabs to spaces
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expr
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Evaluate expressions
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factor
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Print prime factors
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false
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Do nothing, unsuccessfully
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fdformat
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Low-level format a floppy disk
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fdisk
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Partition table manipulator for Linux
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fgrep
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Search file(s) for lines that match a fixed string
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find
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Search for files that meet a desired criteria
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fmt
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Reformat paragraph text
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fold
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Wrap text to fit a specified width
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format
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Format disks or tapes
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free
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Display memory usage
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fsck
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Filesystem consistency check and repair
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gawk
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Find and Replace text within file(s)
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grep
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Search file(s) for lines that match a given pattern
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groups
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Print group names a user is in
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gzip
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Compress or decompress named file(s)
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head
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Output the first part of file(s)
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hostname
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Print or set system name
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id
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Print user and group id’s
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info
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Help info
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install
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Copy files and set attributes
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join
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Join lines on a common field
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kill
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Stop a process from running
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less
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Display output one screen at a time
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ln
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Make links between files
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Find files
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logname
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Print current login name
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lpc
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Line printer control program
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lpr
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Off line print
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lprm
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Remove jobs from the print queue
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List information about file(s)
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man
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Help manual
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mkdir
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Create new folder(s)
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mkfifo
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Make FIFOs (named pipes)
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mknod
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Make block or character special files
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more
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Display output one screen at a time
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mount
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Mount a file system
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mv
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Move or rename files or directories
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nice
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Set the priority of a command or job
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nl
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Number lines and write files
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nohup
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Run a command immune to hangups
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passwd
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Modify a user password
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paste
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Merge lines of files
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pathchk
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Check file name portability
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pr
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Convert text files for printing
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printcap
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Printer capability database
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printenv
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Print environment variables
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printf
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Format and print data
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ps
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Process status
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Print Working Directory
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quota
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Display disk usage and limits
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quotacheck
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Scan a file system for disk usage
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quotactl
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Set disk quotas
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ram
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ram disk device
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rcp
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Copy files between two machines
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rm
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Remove files
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rmdir
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Remove folder(s)
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rpm
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Remote Package Manager
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rsync
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Remote file copy (Synchronize file trees)
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screen
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Terminal window manager
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sdiff
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Merge two files interactively
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sed
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Stream Editor
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select
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Accept keyboard input
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seq
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Print numeric sequences
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shutdown
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Shutdown or restart linux
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sleep
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Delay for a specified time
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sort
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Sort text files
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split
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Split a file into fixed-size pieces
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Su UserName
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Substitute user identity(Switch user)
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sum
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Print a checksum for a file
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symlink
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Make a new name for a file
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sync
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Synchronize data on disk with memory
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tac
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Concatenate and write files in reverse
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tail
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Output the last part of files
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tar
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Tape Archiver
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tee
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Redirect output to multiple files
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test
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Evaluate a conditional expression
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time
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Measure Program Resource Use
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touch
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Change file timestamps
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top
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List processes running on the system
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traceroute
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Trace Route to Host
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tr
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Translate, squeeze, and/or delete characters
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true
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Do nothing, successfully
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tsort
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Topological sort
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tty
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Print filename of terminal on stdin
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umount
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Unmount a device
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uname
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Print system information
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unexpand
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Convert spaces to tabs
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uniq
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Uniquify files
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units
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Convert units from one scale to another
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unshar
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Unpack shell archive scripts
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useradd
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Create new user account
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usermod
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Modify user account
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users
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List users currently logged in
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uuencode
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Encode a binary file
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uudecode
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Decode a file created by uuencode
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vdir
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Verbosely list directory contents (`ls -l -b’)
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watch
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Execute/display a program periodically
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wc
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Print byte, word, and line counts
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whereis
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Report all known instances of a command
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which
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Locate a program file in the user’s path
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who
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Print all usernames currently logged in
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whoami
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Print the current user id and name (`id -un’)
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xargs
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Execute utility, passing constructed argument list(s)
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yes
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Print a string until interrupted
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