How to count number of words from String using shell

Question

I want to count number of words from a String using Shell.

Suppose the String is:

input=\"Count from this String\"

Here the delimit

Answer 1

To do it in pure bash avoiding side-effects, do it in a sub-shell:

$ input="Count from this string "
$ echo $(IFS=' '; set -f -- $input; echo $#)
4

It works with other separators as well:

$ input="dog,cat,snake,billy goat,horse"
$ echo $(IFS=,; set -f -- $input; echo $#)
5
$ echo $(IFS=' '; set -f -- $input; echo $#)
2

Note the use of "set -f" which disables bash filename expansion in the subshell, so if the caller wants expansion it should be done beforehand (Hat Tip @mkelement0).