I came up with a basic one to help automate the process of removing a number of folders as they become unneeded.
#!/bin/bash rm -rf ~/myfolder1/$1/anotherfolder rm -rf ~/myfolder2/$1/yetanotherfolder rm -rf ~/myfolder3/$1/thisisafolder
This is evoked like so:
./myscript.sh <{id-number}>
The problem is that if you forget to type in the id-number
(as I did just then), then it could potentially delete a lot of things that you really don't want deleted.
Is there a way you can add any form of validation to the command line parameters? In my case, it'd be good to check that a) there is one parameter, b) it's numerical, and c) that folder exists; before continuing with the script.
$1 means an input argument and -z means non-defined or empty. You're testing whether an input argument to the script was defined when running the script. Follow this answer to receive notifications.
To find out if a bash variable is defined: Return true if a bash variable is unset or set to the empty string: if [ -z ${my_variable+x} ]; Also try: [ -z ${my_bash_var+y} ] && echo "\$my_bash_var not defined"
#!/bin/sh die () { echo >&2 "$@" exit 1 } [ "$#" -eq 1 ] || die "1 argument required, $# provided" echo $1 | grep -E -q '^[0-9]+$' || die "Numeric argument required, $1 provided" while read dir do [ -d "$dir" ] || die "Directory $dir does not exist" rm -rf "$dir" done <<EOF ~/myfolder1/$1/anotherfolder ~/myfolder2/$1/yetanotherfolder ~/myfolder3/$1/thisisafolder EOF
edit: I missed the part about checking if the directories exist at first, so I added that in, completing the script. Also, have addressed issues raised in comments; fixed the regular expression, switched from ==
to eq
.
This should be a portable, POSIX compliant script as far as I can tell; it doesn't use any bashisms, which is actually important because /bin/sh
on Ubuntu is actually dash
these days, not bash
.
The sh
solution by Brian Campbell
, while noble and well executed, has a few problems, so I thought I'd provide my own bash
solution.
The problems with the sh
one:
~/foo
doesn't expand to your homedirectory inside heredocs. And neither when it's read by the read
statement or quoted in the rm
statement. Which means you'll get No such file or directory
errors.grep
and such for basic operations is daft. Especially when you're using a crappy shell to avoid the "heavy" weight of bash.echo
.sh
can cope with them - which is why I almost always prefer bash
, it's far more bulletproof & harder to exploit when used well).While, yes, using /bin/sh
for your hashbang means you must avoid bash
isms at all costs, you can use all the bash
isms you like, even on Ubuntu or whatnot when you're honest and put #!/bin/bash
at the top.
So, here's a bash
solution that's smaller, cleaner, more transparent, probably "faster", and more bulletproof.
[[ -d $1 && $1 != *[^0-9]* ]] || { echo "Invalid input." >&2; exit 1; } rm -rf ~/foo/"$1"/bar ...
$1
in the rm
statement!-d
check will also fail if $1
is empty, so that's two checks in one.=~
in bash, you should be putting the regular expression in a variable. In any case, globs like mine are always preferable and supported in far more bash versions.If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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