How can I use the UNIX shell to count the number of times a letter appears in a text file?

Question

I have a few text files and I\'d like to count how many times a letter appears in each?

Specifically, I\'d like to use the UNIX shell to do this, in the form of: cat fil

Answer 1

Alternative to grep:

sed 's/[^x]//g' filename | tr -d '\012' | wc -c

where x is the character you want to count.