cut is an incredibly use command but it can be frustrating to use on columar data with a variable number of spaces between columns. awk is often a better alternative in that case but, IMHO, it often feels more nature to use cut in a shell pipeline rather than a quoted onliner awk expression.

I recently stumbled across this trick (which I suspect I’ve discovered and forgotten more than once) of using tr to compress multi-space field seperators into a since character.

Consider this simple example of finding the ammount of free memory on the system:

$ free
             total       used       free     shared    buffers     cached
Mem:       7731688    5692336    2039352     396756     740020    2239136
-/+ buffers/cache:    2713180    5018508
Swap:      7733244          0    7733244
$ free | grep Mem: | cut -d ' ' -f4

$ free | grep Mem: | tr -s ' ' | cut -d ' ' -f4
2037816