Sysadmins offen happen upon simple tasks for which there’s no actual shell command. For example, you may want to run a command after a random delay of up to 3 minutes. Well, there’s
sleep and there’s
$RAND, so you’ll probably quickly solve that problem. If you need to do this more often, you’ll likely build some kind of script to make this task as easy as possible.
ago: Show how long ago a file/directory was modified in a human-readable fashion.
dupes: Report on duplicate files, via a SHA1 hash of the contents, recursively.
empty-dir: Indicate, via return code, whether a given directory is empty or not.
maybe: In a similar vain to true and false the maybe command exits with a status code of zero or one, depending on a random number.
multi-ping: Ping a host, regardless of whether it is an IPv6 or IPv4 host.
mysql-slave-check: If the current host is a MySQL slave this script will test that the slave replication is still working.
randpass: Generate a single random password via /dev/urandom.
since: Show the new output since previously reading a file. This is useful for keeping track of logfile updates.
splay: Sleep for a random amount of time, limited by the given max value. (Default is 5 minutes).
ssl-expiry-date: Report the date, and number of days, until the given SSL certificate expires.
timeout: Timeout allows you to run a command which will be killed after the given number of seconds.
until-success: Repeat the specific command until it succeeds – run at least once always.
which-shell: Identify the shell we’re running under.
with-lock: Run a command, unless an existing copy of that command is already running, via the creation of a temporary lockfile.