Untitled

If shell script file
if [ '/*, *, [3,5],/d' ]; then
    echo 'ok'
else
    echo'fail'
fi

#!/bin/bash
# tested with bash 4
while read -r x x Y x
do
  case "$Y" in
   "3," ) echo "ok";;
   *) echo "Not ok";;
  esac
done < file

#!/bin/sh
# let's create the input file
echo '5, 2, 3, 5' > /tmp/myfile

# function will output third argument
third() { IFS=', '; echo $3; }

# now let's print the third value from the input file
third $(cat /tmp/myfile)

#!/bin/sh
THIRD=$(awk -F', ' '{print $3}' < /tmp/myfile)