Everything my dear colleague RudiC said applies, but also, just to show you that posting your stuff is a rewarding activity:

Under NO circumstances you should use backticks any more! If you are not the rare exception who uses an original Bourne shell from the time computers ran on steam instead of electrical power you have a shell that can (and should) use "POSIX style" subshells:

Code:

prior=$(lpstat -o |grep -v bytes |wc -l)

The same applies here but in addition the grep can be straightened. The sort is superfluous because you want to know the number of lines at the end which is independent of the sorting:

Code:

cleaned=$( lpstat -o | grep -ve bytes -ve "${day1}" -ve "${day2}" -ve "${day3}" | wc -l )

I hope this helps.

bakunin