since is a unix utility similar to tail. Unlike tail, since only shows the lines appended since the last time. It is useful to monitor growing log files
The below example shows how since can be used to quickly track down a change in /var/log:
~# since /var/log/* >& /dev/null ~# logger "hello world" ~# since /var/log/* ... ==> /var/log/messages [nothing new] <== ==> /var/log/user.log <== May 5 13:11:34 hostname root: hello world ...
This is useful when one wants to locate an error message - simply trigger the error in place of running logger in the above example
since can be useful in a shell alias (add to ~/.bashrc) to monitor important log files, as shown below
alias dosince='since /var/log/{syslog,kern.log,apache/error.log}'