Trying to rename bulk folders using standard tools

Question

I am trying to bulk rename many folders but for some reason my approach does not seem to work. I am trying to use the following script but it does nothing. I am new to programming so any suggestions are appreciated. These are the folder names that i have.

test.custom.tmp         untitledfolder.custom.tmp   wis.custom.tmp

I need them renamed to

test untitledfolder wis

I am using the following script but it does nothing.

while read line; do
  newname=$(echo "$line" | cut -f 1 -d '_')
  mv $line newname;
done < read

Here i created a file called read with all the foldernames that need renaming.

What is wrong with this script and also is there a better way to get this done? Thanks.

Answer 1

A simple way would be:

$ for d in *.custom.tmp/; do 
    echo mv -- "$d" "${d%%.*}"
  done
mv -- test.custom.tmp/ test
mv -- untitledfolder.custom.tmp/ untitledfolder
mv -- wis.custom.tmp/ wis

Once you are sure that's the result you want, remove the echo.

---

The ${d%%.*} is a parameter expansion, precisely:

${parameter%word}

${parameter%%word}

The word is expanded to produce a pattern and matched according to the rules described below (see Pattern Matching). If the pattern matches a trailing portion of the expanded value of parameter, then the result of the expansion is the value of parameter with the shortest matching pattern (the ‘%’ case) or the longest matching pattern (the ‘%%’ case) deleted.

In this case it takes the string for example test.custom.tmp and removes everythig after the first ..

Answer 2

If you want to keep your aproach, you can do something like:

while read line; do
  newname=$(echo "$line" | cut -f 1 -d '.');
  mv $line $newname;
done < read

Just keep in mind that your delimiter is a point (-d '.'), and also use the $newname as a variable, not as a string.

This corrects your scripts errors, but for a better approach you can use @schrodingerscatcuriosity answer.