Use 'cd ... || exit' or 'cd ... || return' in case cd fails. Open
cd "$BP"
- Read upRead up
- Exclude checks
Use cd ... || exit in case cd fails.
Problematic code:
cd generated_files
rm -r *.c
func(){
cd foo
do_something
}
Correct code:
cd generated_files || exit
rm -r *.c
# For functions, you may want to use return:
func(){
cd foo || return
do_something
}
Rationale:
cd
can fail for a variety of reasons: misspelled paths, missing directories, missing permissions, broken symlinks and more.
If/when it does, the script will keep going and do all its operations in the wrong directory. This can be messy, especially if the operations involve creating or deleting a lot of files.
To avoid this, make sure you handle the cases when cd
fails. Ways to do this include
-
cd foo || exit
as suggested to just abort immediately -
if cd foo; then echo "Ok"; else echo "Fail"; fi
for custom handling -
<(cd foo && cmd)
as an alternative to<(cd foo || exit; cmd)
in<(..)
,$(..)
or( )
Exceptions:
ShellCheck does not give this warning when cd
is on the left of a ||
or &&
, or the condition of a if
, while
or until
loop. Having a set -e
command anywhere in the script will disable this message, even though it won't necessarily prevent the issue.
If you are accounting for cd
failures in a way shellcheck doesn't realize, you can disable this message with a [[directive]].
Notice
Original content from the ShellCheck https://github.com/koalaman/shellcheck/wiki.
Consider using { cmd1; cmd2; } >> file instead of individual redirects. Open
echo "HTTP_HOST=http://$CURRENT_DIR_NAME.127.0.0.1.nip.io/" >> ../.m2install.conf
- Read upRead up
- Exclude checks
Consider using { cmd1; cmd2; } >> file instead of individual redirects.
Problematic code:
echo foo >> file
date >> file
cat stuff >> file
Correct code:
{
echo foo
date
cat stuff
} >> file
Rationale:
Rather than adding >> something
after every single line, you can simply group the relevant commands and redirect the group.
Exceptions
This is mainly a stylistic issue, and can freely be ignored.
Notice
Original content from the ShellCheck https://github.com/koalaman/shellcheck/wiki.