Master Linux File Renaming: Sed, Substring Tricks & Extension Swaps

1. Replace text with 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

2. Rename files using variable substring expansion

vi laolang.log
wolf_20170806_1_wolf.jpg
wolf_20170806_2_wolf.jpg
wolf_20170806_3_wolf.jpg
wolf_20170806_4_wolf.jpg
wolf_20170806_5_wolf.jpg
wolf_20170806_6_wolf.jpg
wolf_20170806_7_wolf.jpg
wolf_20170806_8_wolf.jpg
wolf_20170806_9_wolf.jpg
wolf_20170806_10_wolf.jpg
# f=wolf_20170806_10_wolf.jpg
# echo $f
wolf_20170806_10_wolf.jpg
# echo ${f%wolf*.jpg}
wolf_20170806_10_
# mv $f echo ${f%wolf*.jpg}.jpg
# for f in ls *wolf.jpg ;do mv $f echo ${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}
# for f in ls *.jpg ;do mv $f ${f/%jpg/log} ;done