How do I make bash warn me when overwriting an existing file?

Question

I think the title is pretty self-explanatory. All i want is bash to warn me whenever I attempt to overwrite an existing while using cp or mv. I'd really appreciate some help. :)

score 59 · Accepted Answer · answered Jan 05 '13 at 10:50

59

You should use the interactive mode which makes sure you get a 'prompt before overwrite'

cp --interactive
mv --interactive

Or in short

cp -i
mv -i

Type man cp or man mv on your command line to find out more.

answered Jan 05 '13 at 10:50

don.joey

28,662

3

So i guess those to commands go as aliases in my .bashrc as well. Thanks a lot. Appreciate your help. :) – sayantankhan Jan 05 '13 at 11:33
5

Indeed! You can append something like alias rm='rm -i' to your .bashrc or better your .bash_aliases. Read more in the post How do I create a permanent Bash alias? – don.joey Jan 05 '13 at 11:40
2

But i just thought of something. What about some of the scripts i've written. Will they use the aliased cp and mv or the normal one? – sayantankhan Jan 06 '13 at 09:44
@Bolt64 It depends on where you put your alias definition, but usually it will use the normal one. – Jan Warchoł May 06 '16 at 09:12

glenn jackman · Answer 2 · 2013-12-24T07:43:25.797

You also want to put set -o noclobber in your .bashrc. This will raise an error if you try to overwrite an existing file by output redirection.

$ set -o noclobber
$ echo one > afile
$ echo two > afile
bash: afile: cannot overwrite existing file

You can force the redirection to work with special syntax:

$ echo two >| afile
$ cat afile
two

http://www.gnu.org/software/bash/manual/bashref.html#Redirecting-Output

How do I make bash warn me when overwriting an existing file?

2 Answers2