Regex help

the_gripmaster · 09-18-2012, 09:37 PM

This is just a simple script which echoes to the screen whatever the user types and quits when the user types quit or QUIT.

Code:

while read LINE; do 
  if [[ "$LINE" =~ quit|QUIT ]]; then 
    break
  fi 
  echo $LINE
done

How do I add case insensitivity to the quit word so that typing in quit, QuIt, Quit, or any other possibility matches the if statement?

tc_ · 09-18-2012, 10:21 PM

Try

Code:

if [[ $(echo $LINE | tr [:lower:] [:upper:]) = "QUIT" ]]; then
    break
fi

See also the man page of 'tr'.

firstfire · 09-18-2012, 10:35 PM

Hi.

You can also use

Code:

shopt -s nocasematch

to enable case-insensitive matching:

man bash:

Quote:

nocasematch
If set, bash matches patterns in a case-insensitive fashion when performing matching while executing case or [[ conditional commands.

grail · 09-19-2012, 10:53 AM

Or if bash is version 4 or greater:

Code:

[[ ${LINE^^} == QUIT ]] && break