filename extension check - regular expression

Shell Programming and Scripting
1

How to compare the file name for "zip" or "ZIP" extension.

I can put one more || condition to check the upper case in the below:
if [[ "`echo ${fileName} | cut -d'.' -f2`" = "zip" ]]; then

Is there any better way to compare using regular expressions.

Thx in advance.

2

Try..

case $fileName in 
       *.ZIP|*.zip) echo true ;; 
       *) echo false ;; 
esac
3

You can get the suffix from a filename without using an external (i.e., slow) command:

suffix=${filename##*.}

... but it's not necessary to do that.

Use pattern matching (not regular expressions) in a case statement:

case $filename in
   *.[zZ][iI][pP]) true ;;
   *) false ;;
esac
4

the below command will chop the extension of a given file and convert it into lowercase.You can put this in a test statement to compare the ext.

echo "${filename##*.}" | tr 'A-Z' 'a-z'

5

Got it. Thank you all.