Technique

Here is the basic procedure (in Bash) for comparing two strings to see if they match:

case $string in 
  $pattern) echo "Match" ;;
  *) echo "No match";; 

Using the case statement, and assuming $pattern has already been handed to the shell, the next input ($string) will be compared with $pattern to see if they match.

If they do, the line will type out “match.”

If not, the case statement will execute the second line of the script, which basically says if the line is anything(*) then it will type out “no match.”

With the case operation, the second line here executes if the first line doesn’t execute (because the string does not match)

From Linux.com (“Patterns in string processing in shell scripts“)

–Joab Jackson