filename='myfile.20240101.txt'
filename2='otherfile.20240303.txt'
filename3='anotherfile.2025.txt'

I want to remove the middle part between the dots. I will take a look at awk, but is there an 'easier' way?

base.numbers.txt

filename='myfile.20240101.txt'
filename2='otherfile.20240303.txt'
filename3='anotherfile.2025.txt'

I want to remove the middle part between the dots. I will take a look at awk, but is there an 'easier' way?

base.numbers.txt

• bash

• 6 newfilename="${filename%%.*}.${filename##*.}"? Or [[ $filename =~ ^(.*)\..*(\..*)$ ]] && newfilename="${BASH_REMATCH[1]}${BASH_REMATCH[2]}"? – Renaud Pacalet Commented Mar 21 at 13:09
• 1 In all your examples, the filenames end in .txt. Is this a general rule? If so, you should say it in your question, because in this case, a trivial solution would be newname=${filename/.*/}.txt. – user1934428 Commented Mar 21 at 14:05
• Re "I will take a look at awk": How about awk -F . '{print $1 "." $NF}'? – pmf Commented Mar 21 at 15:16
• myfile.20240101.txt -> myfile..txt? – Cyrus Commented Mar 21 at 16:03

3 Answers 3

$ filename='myfile.20240101.txt'
$ [[ "$filename" =~ (.*)\..*(\..*) ]] && echo "${BASH_REMATCH[1]}${BASH_REMATCH[2]}"
myfile.txt

Perl file-rename

# Preview changes first (dry-run)
rename -n 's/\.\d+\.txt$/.txt/' *.txt

# Execute renaming
rename 's/\.\d+\.txt$/.txt/' *.txt

• Breakdown: \.\d+\.txt$ Matches . followed by digits \d+ before the final .txt

Alternative Pattern ^{non-numeric suffixes}

rename 's/\..*\.txt$/.txt/' *.txt  # Removes everything between first and last dot

Notes

1. You may consider a backup at any time before you start a batch operation.
2. Use type rename ; whatis !$ ; apt info !$ to check the rename command, which should be installed by default in common distributions
   man perl to learn more, also see the pcre namespace manual.
3. You could also use cut、grep、 vim or bash , but they're not the easier.

#!/bin/bash

directory=${1:-.}

for file in "$directory"/*.*.*; do
    new_name="$(echo "$file" | sed -E 's/(^[^.]+)\..*\.(.*$)/\1.\2/')"
    cp "$file" "$new_name"
done

If you copy this script to a file and give it executable permission you should get your intended result. You might want to change the directory name.

It works by giving sed the name of the file as an input. Sed then removes the numbers which come between two dots

Then cp creates a copy of the renamed file.