Linux renaming files to add _00 after filename before extension

Quick hack that will do what you describe in bash:

cd /directory
for F in `ls -1 |awk -F. '{print $2}'`
do
  mv $F.jpg ${F}_00.jpg
done

For rename usage:

wmoore@bitbucket(/tmp/dowork)$ ls -1
1.jpg
2.jpg
3.jpg
4.jpg
5.jpg
wmoore@bitbucket(/tmp/dowork)$ rename .jpg _00.jpg *.jpg
wmoore@bitbucket(/tmp/dowork)$ ls -1
1_00.jpg
2_00.jpg
3_00.jpg
4_00.jpg
5_00.jpg

Try the following bash script:

find . -type f -name "*.jpg" -print | while read FILE  
  do mv "${FILE}" "`dirname ${FILE}`/`basename ${FILE} .jpg`_00.jpg"
  done

That will find all .jpg files in or below the current directory and insert _00 before .jpg. If you only want it to handle the current directory start the find command with find . -maxdepth 1

Double backslash at the end of the regex means substitute s/(\w+).jpg$1_00.jpg$ with an empty string.

I used this:

rename 's/\.jpg/_00.jpg/' *.jpg

I am not familiar with rename, but your regex doesn't look right. It appears like you are trying to match files named like this AGPNDRAH01.jpg.AGPNDRAH01_00.jpg and change their name to nothing.

Are you sure you don't mean something like this instead?

rename 's/(\w+).jpg$/\$1\_00.jpg/' *

I have a variant of redhat, and rename doesn't support the 's/' command. Here's a one-liner for you (You have to backslash parenthesis and plus-signs to get the functionality in sed):

for fl in *.jpg; do mv $fl `echo $fl | sed 's/\(\w\+\).jpg/\1_00.jpg/'`; done

You just had a slash in the wrong place and an unnecessary backslash.

rename 's/(\w+).jpg/$1\_00.jpg/' *