How do I modify filenames in a folder using a bash script?

Question

Whenever I download .docx and .ppt files from my school, they always look like this.

UTF-8"File%20Name%20Example.docx

It's pretty annoying to have to rename the file every time I download one, so I want to create a bash script that will do the work for me.

I have a School folder, so I'd like to do a bash script that searches the entire directory and subdirectories for any files that start with the "UTF-8"" prefix, then.

• Have a for loop that removes the prefix from all files starting with that prefix
• Search the filename for occurences of "%20" and replace it with " "
• Monitor the School folder so that any time I download another file with the prefix, it will run the script and immediately rename it.

I am pretty new to linux. I have been researching for the last two hours and I am confused on what I should do. Any help would be greatly appreciated. Thanks!

Answer 1

A basic example of how to monitor files in a folder with systemd.path (in this case /opt/download).

/etc/systemd/system/download-monitor.path:

[Unit]
Description=Download Monitor
[Path]
PathExistsGlob=/opt/download/UTF8"*
[Install]
WantedBy=multi-user.target

Next, we need to create a .service file with the same basename as the .path file.

/etc/systemd/system/download-monitor.service:

[Unit]
Description=Download Monitor
[Service]
ExecStart=/opt/bin/filecheck.sh

Last the Exec script file.

/opt/bin/filecheck.sh:

#!/bin/bash
shopt -s nullglob extglob
systemd.path does not pass what changed so we
rename all .docx and .ppt files starting with
UTF8" in the $a folder.
a=/opt/download
for b in $a/UTF8"*@(.docx|.ppt); do
    c="$a/${b#$a/UTF8"}"
    mv "$b" "$c" && deurlname "$c"
done

^{The deurlname command is found in the renameutils package.}

Now we can enable and start our path monitor:

$ systemctl enable download-monitor.path
$ systemctl start  download-monitor.path

Answer 2

You could use incron for this purpose. It is like a cron, but uses events as triggers.

sudo apt install incron
sudo systemctl enable incron

Add your current user to /etc/incron.allow file:

$ sudo cat /etc/incron.allow 
[sudo] password for myuser: 
myuser

After you've added your user to that file, you could edit incrontab file by that user:

incrontab -e
/home/myuser/test/utfnames      IN_CREATE       /home/myuser/test/renamefiles.sh

As you can see, the first column contains directory path, the second contains watched event (file creation), the third contains command or path to script.

The script contains the next:

for file in /home/myuser/test/utfnames/*
  do mv $file "$(echo $file | sed 's/UTF-8//' | sed 's/%20/ /g')"
done

Do not forget to chmod +x /home/myuser/test/renamefiles.sh

Testing:

myuser@ubuntu:~$ touch 'test/utfnames/UTF-8"Some%20File%20Name.docx'
myuser@ubuntu:~$ touch 'test/utfnames/UTF-8"Some%20File%20Name%202.docx'
myuser@ubuntu:~$ sudo systemctl start incron.service 
myuser@ubuntu:~$ ls test/utfnames/
'UTF-8"Some%20File%20Name%202.docx'  'UTF-8"Some%20File%20Name.docx'
myuser@ubuntu:~$ touch 'test/utfnames/UTF-8"Some%20File%20Name%203.docx'
myuser@ubuntu:~$ ls test/utfnames/
'"Some File Name 2.docx'  '"Some File Name 3.docx'  '"Some File Name.docx'