my code:
execInPath() { prev_dir=${PWD##*/} cd $1 shift res=$($@) cd prev_dir echo res } alias path=execInPath $ path ~ ls gives: bash: cd: prev_dir: No such file or directory (and the files in my home directory prior to that)
3 Answers
You must use "$prev_dir" to reference variable prev_dir:
execInPath() { prev_dir=${PWD##*/} cd -P -- "$1" shift res=$( "$@" ) cd -- "$prev_dir" printf '%s\n' "$res" } alias path=execInPath But using a subshell is easier:
execInPath() { : 'Change directory in subshell' ( cd -- "$1" || return 1 shift res=$( "$@" ) printf '%s\n' "$res" ) : 'Back to previous dir' pwd } alias path=execInPath 
Use a subshell:
execInPath() (cd -P -- "$1" && shift && exec "$@") Notes:
- You need to check the exit status of
cdas ifcdfails, you'd run the command in the wrong directory. - if you want
cdto behave like in other languages, you need-P. - think of the exit status of your function. Here, you want it to be unsuccessful if
cdfails, and be the exit status of"$@"otherwise. $@must be quoted always.- It's impossible to do
cd some-dir;...;cd original-dirand get back to the same original directory 100% reliably.
answered Feb 2, 2016 at 17:08
Stéphane Chazelas
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- This also came into my mind at first, but it seems that the OP want to do other things inside function after go back to previous dir.cuonglm– cuonglm2016-02-02 17:13:33 +00:00Commented Feb 2, 2016 at 17:13
- Would you mind explaining more details about behave like in other languages, what's other languages?cuonglm– cuonglm2016-02-02 17:14:57 +00:00Commented Feb 2, 2016 at 17:14
- @cuonglm, the chdir or C, perl, python, ruby, java, you name it.Stéphane Chazelas– Stéphane Chazelas2016-02-02 17:25:55 +00:00Commented Feb 2, 2016 at 17:25
When you assign a variable in bash, there is no $ (unlike perl), but when you use/refer to a variable in bash, you need to add the $ to it. Your cd prev_dir should be cd $prev_dir.
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cd $prev_dirdoesn't make sense. It should be at leastcd "$prev_dir"or rathercd -P -- "$prev_dir".Stéphane Chazelas– Stéphane Chazelas2016-02-02 17:10:57 +00:00Commented Feb 2, 2016 at 17:10 - Not sure why it doesn't make sense. The quotes are not required.
export prev_dir="/bin";cd $prev_dirworks just fine.Tim S.– Tim S.2016-02-02 17:18:14 +00:00Commented Feb 2, 2016 at 17:18 - @TimS.: See unix.stackexchange.com/q/171346/38906 and unix.stackexchange.com/q/131766/38906cuonglm– cuonglm2016-02-02 17:22:49 +00:00Commented Feb 2, 2016 at 17:22
- See Security implications of forgetting to quote a variable in bash/POSIX shells, Why does my shell script choke on whitespace or other special characters?, When is double-quoting necessary?, Expansion of a shell variable and effect of glob and split on it, Quoted vs unquoted string expansion...Stéphane Chazelas– Stéphane Chazelas2016-02-02 17:24:29 +00:00Commented Feb 2, 2016 at 17:24
- While I agree that it's a security issue, that's far from "doesn't make sense". Personally I don't use bash for a number of reasons, but that's beside the point. Thanks for the links.Tim S.– Tim S.2016-02-02 17:56:34 +00:00Commented Feb 2, 2016 at 17:56
cd $prev_dirinstead ofcd prev_dir; maybe alsoecho $res