I have 3 files in one directory like below:
file_str_23.txt
file_jan_24.txt
file_feb_25.txt
Here I would like to replace the first file name 'file_str' with 'file_', so finally the file name should be 'file_23.txt'.
The problem is that I don't know the exact number in the file name, so I should go with 'file_str' string only.
How to do this?
To change single file's name, use mv:
mv file_str_23.txt file_23.txt
And if you want to do this in batch, you could try rename, which accepts regular expression:
rename 's/_.*?_/_/' file_*
First argument is a Perl regex substitution expression. It's general form is:
s/WHAT_TO_LOOK_FOR/WHAT_TO_PUT_INSTEAD/
In our case WHAT_TO_LOOK_FOR is _.*?_ and WHAT_TO_PUT_INSTEAD is _.
Now, _.*?_ means: "Match underscore followed by any number of any characters (.*?), followed by another underscore". For instance, in string "file_str_23.txt" it will match "str".
This matched part of the file name will be replaced with _ (our WHAT_TO_PUT_INSTEAD part).
if you're using bash, you could also use this
for F in file_*.txt ; do
mv ${F} file_${F#file_*_}
done
Which is super easy to make into a one-liner:
for F in file_*.txt ; do mv ${F} file_${F#file_*_} ; done
You can try this for loop that should work without any external utility:
for f in *_*_*.txt; do
mv "$f" "${f/_*_/_}"
done
