Shell script to rename files

Question

I have a shell script:

#!/bin/bash
for name in /home/imp/imp/msgs/$1.PK1; do
    mv "$name" "${name%.PK1}.BRD" 2>/dev/null >/dev/null
done
for name in /home/imp/imp/msgs/$1.PK2; do
    mv "$name" "${name%.PK2}.MIX" 2>/dev/null >/dev/null
done

It works, but only on pre-existing files. What happens, is that more *.PK1 and *.PK2 are created after the initial scan. I'd like this script to "loop" and rename the files that are created afterwards. Is this possible?

UPDATE:

This is what I have now:

#!/bin/bash

while [ ! -z "$(ls *.PK1 *.PK2 2>/dev/null)" ]; do

for name in /home/imp/imp/msgs/$1.PK1; do
    mv "$name" "${name%.PK1}.BRD" 2>/dev/null >/dev/null
done
for name in /home/imp/imp/msgs/$1.PK2; do
    mv "$name" "${name%.PK2}.MIX" 2>/dev/null >/dev/null
done
sleep 1; done

Is that correct?

Thanks.

Please show usage of this script. And 2>/dev/null >/dev/null what is that. if you want to redirect stdout and stderr to /dev/null just use <command> > /dev/null 2>&1 — darvark, Mar 24 '17 at 05:51
So you want this script to be started once and then loop forever and rename all newly created .PK# files? Why not place a while true; do and sleep 1; done around your stuff? Adapt the sleep according to your expectations on how long it may take until new files will be renamed. But don't even think of removing it. — Philippos, Mar 24 '17 at 06:01
Put it all inside a while loop that tests for the existence of .PK1 or .PK2, like so: `while [ ! -z "$(ls .PK1 .PK2 2>/dev/null)" ]; do [YOUR CODE HERE]; sleep 1; done' — MikeD, Mar 24 '17 at 06:05
Good idea, but where to I place thew while true; doand `sleep ;1' at? — ignatius, Mar 24 '17 at 06:05
Where do I place the while [ ! -z "$(ls *.PK1 *.PK2 2>/dev/null)" ]; do at? — ignatius, Mar 24 '17 at 06:11
Your script will now rename files and stop once there are no new files for once second. Is that your desired behaviour? — Philippos, Mar 24 '17 at 07:53
Ok. I know the problem. It's that the script takes an argument. I need to make it scan through all of the *.PK1 and *.PK2 files. — ignatius, Mar 24 '17 at 08:13
OK. I changed $1.PK1 and $1.PK2 to *.PK1 and *.PK2, the problem is still that the script doesn't terminate. — ignatius, Mar 24 '17 at 08:18
Cool, glad it works now! Please upvote the comments that helped you so people get reputation credit. — MikeD, Mar 24 '17 at 08:55
@MikeD comments give no reputation. And answers belong in answers, not comments. Comments can be deleted with no warning and should only be used to ask for clarification. Also, using ls like that is very bad practice. See ikkachu's answer for a way to do it safely. — terdon, Mar 24 '17 at 09:40

score 2 · Answer 1 · edited Apr 13 '17 at 12:37

2

Is there some reason to use $1 in for name in /path/$1.PK1 instead of just for name in /path/*.PK1? Do you pass a glob pattern to the script on purpose?

If you want to catch all files with those suffixes and new ones as they appear, a simple solution in Bash would something like this:

shopt -s nullglob
dir=/home/imp/imp/msgs
while true ; do
    for name in "$dir/"*.PK1; do
        mv "$name" "${name%.PK1}.BRD" 2>/dev/null >/dev/null
    done
    for name in "$dir/"*.PK2; do
        mv "$name" "${name%.PK2}.MIX" 2>/dev/null >/dev/null
    done
    sleep 1
done

If you want to avoid doing extra work, you could (on Linux) use something like inotifywait to wait for new files to appear, e.g. as in here: How to use inotifywait to watch a directory for creation of files of a specific extension

edited Apr 13 '17 at 12:37

Community

1

answered Mar 24 '17 at 08:56

ilkkachu

138,973

One last question regarding this script: can it run in the background, while another program is running? If not, any way I can make it do so? – ignatius Apr 07 '17 at 00:32
@ignatius, tell the shell to run it in the background (see http://mywiki.wooledge.org/ProcessManagement ), run it in another terminal or another screen or tmux window, ... – ilkkachu Apr 07 '17 at 08:43

Shell script to rename files

1 Answers1