spiritech
April 24th, 2013, 02:53 PM
i was looking through some old posts to try and find alternatives to renaming files during a while loop and found this old post by vaphell
ext="mp4"
while read -r var
do
echo "normal: $var"
echo "new ext: ${var%.???}.$ext"
echo "new ext(2): ${var%.[a-zA-Z][a-zA-Z][a-zA-Z0-9]}.$ext"
done < input
i didnt read into it much back when it was posted as i didnt have much experience with bash. i have tested it today and found it is a much cleaner way of renaming files during a for - or while - loop. instaed of my sulotion of using a pipe then sed command. i understand most of whats going on in the code.
echo "normal: $var" outputs the unaltered input
echo "new ext: ${var%.???}.$ext" ouputs the input with a new extension.
i assume that using the {} enters the variable into a bash substitution, the "." means a dot and the ??? means any 3 digits. i also assume that the % defines last occurance or from end of line non-greedy the same kind of function $ has in sed.
i would like to understand things further. how can i use defferent matching criteria i.e. any. all or first occurance etc? does it support this kind of matching? is there a tutorial covering this subject?
spiritech
ext="mp4"
while read -r var
do
echo "normal: $var"
echo "new ext: ${var%.???}.$ext"
echo "new ext(2): ${var%.[a-zA-Z][a-zA-Z][a-zA-Z0-9]}.$ext"
done < input
i didnt read into it much back when it was posted as i didnt have much experience with bash. i have tested it today and found it is a much cleaner way of renaming files during a for - or while - loop. instaed of my sulotion of using a pipe then sed command. i understand most of whats going on in the code.
echo "normal: $var" outputs the unaltered input
echo "new ext: ${var%.???}.$ext" ouputs the input with a new extension.
i assume that using the {} enters the variable into a bash substitution, the "." means a dot and the ??? means any 3 digits. i also assume that the % defines last occurance or from end of line non-greedy the same kind of function $ has in sed.
i would like to understand things further. how can i use defferent matching criteria i.e. any. all or first occurance etc? does it support this kind of matching? is there a tutorial covering this subject?
spiritech