Create new file but add number if filename already exists in bash

Question

I found similar questions but not in Linux/Bash

I want my script to create a file with a given name (via user input) but add number at the end if filename already ex

Answer 1

Use touch or whatever you want instead of echo:

echo file$((`ls file* | sed -n 's/file\([0-9]*\)/\1/p' | sort -rh | head -n 1`+1))

Parts of expression explained:

• list files by pattern: ls file*
• take only number part in each line: sed -n 's/file\([0-9]*\)/\1/p'
• apply reverse human sort: sort -rh
• take only first line (i.e. max value): head -n 1
• combine all in pipe and increment (full expression above)