CODEWITHSUNDEEP
linuxshell
druido82
druido82

Reputation: 74

Renaming files from shell by removing letters

I have a lot of jpg files with letters and numbers in their names. I want to remove all letters, for example abc12d34efg.jpg becomes 1234.jpg. For the for loop I thought:

 for i in *.jpg; do mv "$i" ...

but I can't find a command for what I want.

Upvotes: 0

Views: 40

Answers (3)

Dima Chubarov
Dima Chubarov

Reputation: 17169

Here is a oneline solution that uses tr

 for f in *.jpg ; do n="$(echo ${f} | tr -d a-zA-Z )" ; mv "$f" "${n}jpg" ; done

With some formatting it would look like as

 for f in *.jpg ; do 
   n="$(echo ${f} | tr -d a-zA-Z )" 
   mv "$f" "${n}jpg"
 done

Here is what's happening:

First we remove all letters from the name using tr -d a-zA-Z. From abc12d34efg.jpg we get 1234. (with a dot at the end as . does not belong in the a-z and A-Z intervals) and assign this value to variable $n. T

Then we can rename $f to ${n}jpg. That's it.

Update to delete both lower case and upper case letters use tr -d a-zA-Z, to delete only lower case letters use tr -d a-z instead.

Upvotes: 0

Michael Coker
Michael Coker

Reputation: 53674

You can use sed to replace all letters with nothing using regex.

for i in *.jpg; do mv $i `echo $i | sed -e 's/[a-zA-Z]//g'`jpg; done

Upvotes: 1

Benjamin W.
Benjamin W.

Reputation: 52142

With shell parameter expansion:

for fname in *.jpg; do mv "$fname" "${fname//[[:alpha:]]}jpg"; done

"${fname//[[:alpha:]]}" is a substitution of all occurrences of [[:alpha:]] (any letter) with nothing. Because this also removes the jpg, we have to add it again – the appended jpg does that.

Upvotes: 1

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