How to Batch Rename Files with sed and Bash Parameter Expansion

This article provides practical methods for batch renaming files on a Linux system.

1. Rename using sed

# find / -type f -name wolf.log
/wolf.log
/tmp/wolf.log
/root/wolf/wolf.log
# sed -i 's#wolf#yujing#g' find / -type f -name wolf.log
# find / -type f -name "wolf.log" | xargs cat

yujing
yujing
yujing

The sed command replaces the string wolf with yujing directly in the files found.

2. Rename using Bash variable substring replacement

# Example file list
wolf_20170806_1_wolf.jpg
wolf_20170806_2_wolf.jpg
... 
# f=wolf_20170806_10_wolf.jpg
# echo ${f%wolf*.jpg}
wolf_20170806_10_
# mv $f ${f%wolf*.jpg}.jpg

The expression ${f%wolf*.jpg} removes the trailing wolf*.jpg part, allowing the file to be renamed to wolf_20170806_10_.jpg. A loop can process all matching files:

for f in $(ls *wolf.jpg); do mv $f ${f%wolf*.jpg}.jpg; done

3. Change file extensions

# f=wolf_20170806_10_.jpg
# echo ${f/%jpg/log}
wolf_20170806_10_.log
# mv $f ${f/%jpg/log}

The pattern ${f/%jpg/log} substitutes the .jpg suffix with .log. A loop can apply this to all .jpg files:

for f in $(ls *.jpg); do mv $f ${f/%jpg/log}; done

These techniques enable fast, scriptable renaming of large numbers of files without manual intervention.