pipe with rm

I wanted to delete a large number of files in a directory that satisfied a certain criteria in their name.  The command for this is:


find /path/to/dir -name '*criteria*' -exec rm {} \;

or



find /path/to/dir -name '*criteria*'| xargs rm

or


ls | grep criteria | xargs rm

Note: The last command might be slower than the first two.

grep character count

Use grep to count the frequency of a character in a file:

grep o 'character' filename | wc -l