Regex Replace Append Filename

Question

How can I append characters to a files name in linux, using a regex? I've seen these two posts

but haven't been able to get the answers to work for me. I'm also not sure if this belongs here, stack overflow or in another sub-site.

I've been trying

for FILE in \d+_\d+\.png; do echo "$FILE" $(echo "$FILE" | sed 's/\./_t\./'); done

but that doesn't seem to recognize the regexed filename as a regex.

So for data samples my files currently are

1111_2222.png

and I want them to be

1111_2222_t.png

The files are scattered amongst five directories. Thanks.

I want to see the changes before I execute them, just incase I'm doing something stupid. — user3783243, Apr 03 '15 at 19:31
Sure. In bash this should work `for FILE in [0-9]*_[0-9]*.png`. Plus `+` will not work. — baf, Apr 03 '15 at 19:36
@baf `+` works, `\d` doesn't. `+` and `*` are quite different, `*` will allow the value not be present, `+` requires at least one occurrence of the value. — user3783243, Apr 06 '15 at 14:55
I know the difference between `+` and `*`, but plus doesn't work for simple bash expansion. It will work for grep regex, but not in pure bash. See [bash glob patterns](http://mywiki.wooledge.org/BashGuide/Patterns). Anyway I think your script with my tweaks is the simplest solution, no need for grep and other stuff :) — baf, Apr 06 '15 at 19:50

score 3 · Accepted Answer · edited May 23 '17 at 12:41

3

[vagrant@vm-one ~]$ ls
1111_2222.png  1111_4444.png  1111_6666.png
[vagrant@vm-one ~]$ for f in `ls | egrep '[0-9]+_[0-9]+\.png'`; do mv "$f" "${f/.png/_t.png}"; done
[vagrant@vm-one ~]$ ls
1111_2222_t.png  1111_4444_t.png  1111_6666_t.png

Sources

The ls | egrep snippet has been retrieved from here
The mv $f ${f/.png/_t.png} based on this answer

edited May 23 '17 at 12:41

Community

1

answered Apr 03 '15 at 19:41

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score 2 · Answer 2 · answered Apr 03 '15 at 19:37

This works for me in my test..

shopt -s globstar; 
for i in **; do
    test -f ${i} || continue;
    ext=${i##*.};
    echo mv $i ${i%%.${ext}}_t.${ext}; 
done;
shopt -u globstar;

It expects you to be in the correct base directory. Note it makes no assumptions as to what extension the file is or what the 'start' of the filename format is. Be careful.

dawud · Answer 3 · 2015-04-03T23:05:16.380

0

Simple (maybe too much), but also works in this case:

find . -regextype posix-extended \
  -regex '.*[[:digit:]]{4}_[[:digit:]]{4}\.png' \
  -type f -exec rename .png _t.png {} \;

edited Apr 03 '15 at 23:05

answered Apr 03 '15 at 22:58

dawud

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This will rename all pngs though, right? – user3783243 Apr 03 '15 at 23:02
You can always adjust the regex to your needs. – dawud Apr 03 '15 at 23:05
Aha, didn't know about the `-regex` flag. Thanks. I'm not privileged enough to be able to up vote unfortunately. – user3783243 Apr 06 '15 at 14:20

Regex Replace Append Filename

3 Answers3