Loop

Some of the systems monitoring commands with built-in looping functionality, commands such as vmstat, iostat, .... Very often we would like to repeat the same command to monitor certain activities like file size, disk usage.

This shell function does exactly this:

loop()
{
    sec=$1
    shift
    cmd=$*
    while :
    do
    eval $cmd
    sleep $sec
    done
}

Now you just have to provide the interval and the command you like to loop, just like this:

$ loop 5 df -h /
Filesystem             size   used  avail capacity  Mounted on
/dev/md/dsk/d30        5.9G   4.9G   931M    85%    /
Filesystem             size   used  avail capacity  Mounted on
/dev/md/dsk/d30        5.9G   4.9G   931M    85%    /
Filesystem             size   used  avail capacity  Mounted on
/dev/md/dsk/d30        5.9G   4.9G   931M    85%    /
^C