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ul
ulimit
umask
umb-scheme - UMB Scheme ($Revision: 3.2 $)
unalias
uname - print system information
unexpand - convert spaces to tabs
unicode_start - put keyboard and console in unicode mode
unicode_stop - revert keyboard and console from unicode mode
uniq - remove duplicate lines from a sorted file
unix2dos
unlink - call the unlink function to remove the specified file
unset
unzip - list, test and extract compressed files in a ZIP archive
unzipsfx - self-extracting stub for prepending to ZIP archives
updatedb - update the slocate database
uptime - Tell how long the system has been running.
urlview
userinfo - A graphical equivilient to chfn.
usermount - A graphical tool to mount, unmount and format filesystems.
userpasswd - A graphical tool to allow users to change their passwords.
users - print the user names of users currently logged in to the current host
usleep - sleep some number of microseconds
uuidgen - command-line utility to create a new UUID value