During one of my teaching sessions a student asked me if it was possible to find the number of spaces in a variable.
As with all questions in Linux and UNIX the answer is a simple
Of course that’s possible. In UNIX and Linux everything is possible.
With some sed or awk this can be done within
seconds. But I wanted it done completely within
the shell, in this case bash.
This is what I came up with
P="John and Paul and Ringo and George where the Beatles"
R=${P//[! ]/} # Remove everything that is NOT a space
echo ${#R} # Show the number of characters (spaces) that are left
And this also works in the Korn shell (ksh) and the Z-shell (zsh).