How to remove suffix from file in Bash?-CodePudding

I found out that you can apparently add suffix on the fly, this is useful for me to disable a service that relies on the existence of file extension.

$ mv -v file.txt{,.bak}
renamed 'file.txt' -> 'file.txt.bak'

But how can one do the reverse ? What command I have to use ?

$ mv -v file.txt.bak{??}
renamed 'file.txt.bak' -> 'file.txt'

CodePudding user response：

Your command (mv -v file.txt{,.bak}) relies on Bash brace expansion, which translates file.txt{,.bak} to file.txt file.txt.bak. Check out the Bash manpage section for "Brace Expansion". In this case ({,.bak}), there are two strings in the comma-separated list: an empty string and .bak. As such, you can add extensions and the like.

Several examples come to mind for removing extensions using brace expansions (all expanding to mv -iv file.txt.bak file.txt):

mv -iv file.txt{.bak,}
f=file.txt.bak; mv -iv ${f%.bak}{.bak,}, which doesn't presuppose the filename preceding the ".bak" extension (in the Bash manpage, see "Remove matching suffix pattern")
f=file.txt.bak; mv -iv ${f%.*}{.${f##*.},}, which doesn't presuppose any specific extension (in the Bash manpage, additionally see "Remove matching prefix pattern")

As an alternative, and as another contributor suggests, rename is a useful and powerful utility (e.g., rename 's/\.bak$//' *.bak).

P.S. Whenever documenting or scripting variabilized examples, I generally recommend quoting for whitespace safety (e.g., mv -iv "${f%.*}"{."${f##*.}",}).

CodePudding user response：

why donot use rename command.

rename '.bak' '' fileNames

CodePudding user response：

You can use:

file.txt{.bak,}

In this way you substitute the word before the comma with the empty string that is after the comma.