Renaming all files in folder in Bash

Question

How to rename all the files in the directory in such a way the files get added "_1" before ".txt"

apac_02_aug_2017_file.txt
emea_02_May_2017_file.txt
ger__02_Jun_2017_file.txt

To

apac_02_aug_2017_file_1.txt
emea_02_May_2017_file_1.txt
ger__02_Jun_2017_file_1.txt

Answer 1

With rename

rename .txt _1.txt * should do what you are looking for.

To quote man rename:

rename [options] expression replacement file...

rename will rename the specified files by replacing the first occurrence of expression in their name by replacement.

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With common bash commands

Since you said that rename is not installed on your system, here's a solution that uses more standard Bash:

for file in *.txt; do
    mv "$file" "${file%.txt}_1.txt"
done

Explanation: We loop over all files. For each file, we move it to the correct location by making use of something called "parameter expansion" (this is the ${} part). The special character % can be used within parameter expansion to match a pattern at the end of the string and delete it.

For further information, see: http://wiki.bash-hackers.org/syntax/pe#from_the_end

Answer 2

Through mmv it's mush easy:

mmv '*.*' '#1_1.#2' *.txt