Making simple backup alias / function?

Question

OK, so all I really want to do is backup single files as a time in the current directory with '.bak' extension.

Here is my current function that does this (jsyk, using Rocky Linux):

function backup { sudo cp $PWD/$1 $PWD/$1.bak; }

Although, Rocky loads it fine (it's inside ~/.bash_aliases which is loaded from ~/.bashrc, it seems to keep giving me this error:

cp: cannot stat '.bak': No such file or directory

Am I missing something? Or am I crazy for not thinking of something even simpler?

sudo requires -E and -H to preserve environment variables and cp requires -a and -f to keep files metadata and forces overwrite existing .bak — alecxs, Mar 18, 2022 at 18:07
@alecxs if I’m understanding you, it should be “sudo -EH cp -af …”, if so, didn’t work. — GregTheHun, Mar 18, 2022 at 18:12
Well, they aren't local variables, $PWD gives me the current working directory, and $1 I thought was used for posititional variables. Testing this, I used: function test { sudo -EH echo $PWD/$1.bak; } Which seems to give me the proper output: /home/greg/file.txt.bak — GregTheHun, Mar 18, 2022 at 18:19
You could always use echo to get an idea what the command looks like after expansion. — mashuptwice, Mar 18, 2022 at 18:37

GregTheHun · Accepted Answer · 2022-03-18 18:45:08Z

4

Thanks @alecxs, this seemed to work for me:

function backup() { sudo -EH cp -af -- "$1" "$1.bak"; }

answered Mar 18, 2022 at 18:45

GregTheHun

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