shell - Count occurrences of a char in a string using Bash

Question

I need to count the number of occurrences of a char in a string using Bash.

In the following example, when the char is (for example) t, it echos the correct number of occurrences of t in var, but when the character is comma or semicolon, it prints out zero:

var = "text,text,text,text" 
num = `expr match $var [,]`
echo "$num"

Answer 1

you can for example remove all other chars and count the whats remains, like:

var="text,text,text,text"
res="${var//[^,]}"
echo "$res"
echo "${#res}"

will print

,,,
3

or

tr -dc ',' <<<"$var" | awk '{ print length; }'

or

tr -dc ',' <<<"$var" | wc -c    #works, but i don't like wc.. ;)

or

awk -F, '{print NF-1}' <<<"$var"

or

grep -o ',' <<<"$var" | grep -c .

or

perl -nle 'print s/,//g' <<<"$var"