How to have a script work with “$@” or a default list of parameters while not breaking paths with...
I want a script that will run another utility over some default paths if no parameters are passed to it; ideally I want this safe for paths that contain spaces.
So far I have script.sh:
#!/bin/sh
base=$(dirname "$0")
exec touch "${@:-"$base/aaa" "$base/bbb"}"
If I put this into a folder called "foo bar" and run it as:
foo bar/script.sh
I want it to should end up doing:
touch foo bar/aaa foo bar/bbb
i.e. create files "aaa" and "bbb" under "foo bar", the directory in which the script is located.
Instead I get the error
touch: cannot touch 'foo bar/aaa foo bar/bbb': No such file or directory
(If I pass in parameters to the script it seems to work fine. Presumably removing the outer quotes in the last command would reverse my cases.)
shell-script arguments
edited 51 mins ago
Gilles
530k12810631591
asked 1 hour ago
millimoosemillimoose
23315
add a comment |
I want a script that will run another utility over some default paths if no parameters are passed to it; ideally I want this safe for paths that contain spaces.
So far I have script.sh:
#!/bin/sh
base=$(dirname "$0")
exec touch "${@:-"$base/aaa" "$base/bbb"}"
If I put this into a folder called "foo bar" and run it as:
foo bar/script.sh
I want it to should end up doing:
touch foo bar/aaa foo bar/bbb
i.e. create files "aaa" and "bbb" under "foo bar", the directory in which the script is located.
Instead I get the error
touch: cannot touch 'foo bar/aaa foo bar/bbb': No such file or directory
(If I pass in parameters to the script it seems to work fine. Presumably removing the outer quotes in the last command would reverse my cases.)
shell-script arguments
edited 51 mins ago
Gilles
530k12810631591
asked 1 hour ago
millimoosemillimoose
23315
add a comment |
I want a script that will run another utility over some default paths if no parameters are passed to it; ideally I want this safe for paths that contain spaces.
So far I have script.sh:
#!/bin/sh
base=$(dirname "$0")
exec touch "${@:-"$base/aaa" "$base/bbb"}"
If I put this into a folder called "foo bar" and run it as:
foo bar/script.sh
I want it to should end up doing:
touch foo bar/aaa foo bar/bbb
i.e. create files "aaa" and "bbb" under "foo bar", the directory in which the script is located.
Instead I get the error
touch: cannot touch 'foo bar/aaa foo bar/bbb': No such file or directory
(If I pass in parameters to the script it seems to work fine. Presumably removing the outer quotes in the last command would reverse my cases.)
shell-script arguments
edited 51 mins ago
Gilles
530k12810631591
asked 1 hour ago
millimoosemillimoose
23315
I want a script that will run another utility over some default paths if no parameters are passed to it; ideally I want this safe for paths that contain spaces.
So far I have script.sh:
#!/bin/sh
base=$(dirname "$0")
exec touch "${@:-"$base/aaa" "$base/bbb"}"
If I put this into a folder called "foo bar" and run it as:
foo bar/script.sh
I want it to should end up doing:
touch foo bar/aaa foo bar/bbb
i.e. create files "aaa" and "bbb" under "foo bar", the directory in which the script is located.
Instead I get the error
touch: cannot touch 'foo bar/aaa foo bar/bbb': No such file or directory
(If I pass in parameters to the script it seems to work fine. Presumably removing the outer quotes in the last command would reverse my cases.)
shell-script arguments
shell-script arguments
edited 51 mins ago
Gilles
530k12810631591
asked 1 hour ago
millimoosemillimoose
23315
edited 51 mins ago
Gilles
530k12810631591
asked 1 hour ago
millimoosemillimoose
23315
edited 51 mins ago
Gilles
530k12810631591
edited 51 mins ago
Gilles
530k12810631591
edited 51 mins ago
Gilles
530k12810631591
530k12810631591
asked 1 hour ago
millimoosemillimoose
23315
asked 1 hour ago
millimoosemillimoose
23315
asked 1 hour ago
millimoosemillimoose
23315
23315
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
It appears you can't set default parameters in an expansion of ${@:-...}, and "${@:-"$base/aaa" "$base/bbb"}" is expanded as a single string.
If you want to set default parameters you might want to do this:
base=$(dirname -- "$0")
# test explicitly for no parameters, and set them.
if [ "$#" -eq 0 ]; then
set -- "$base/aaa" "$base/bbb"
fi
Then, the "$@" magically quoted parameter substitution can happen unabated:
touch -- "$@"
edited 35 mins ago
Stéphane Chazelas
300k54564916
answered 59 mins ago
glenn jackmanglenn jackman
50.6k570108
OP is using/bin/shso maybeif ((!$#)); thenorif [ $# -eq 0 ]; then?
– Jesse_b
54 mins ago
1
@Jesse_b It's a minor change and the rest works the same, but yes, that made it work for me
– millimoose
51 mins ago
(I like to stick to being dash-compatible if possible for scripts so as to not have to pull in bash into Docker images unnecessarily.)
– millimoose
45 mins ago
About that first sentence,set --; echo ${@:-default}; set -- a b; echo ${@:-default};works (i.e. printsdefaultand thena b) in all shells I tried. Though I don't think you should be able to give a list as a default value, the syntax only mentions a single word there.
– ilkkachu
38 mins ago
add a comment |
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1 Answer
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active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
It appears you can't set default parameters in an expansion of ${@:-...}, and "${@:-"$base/aaa" "$base/bbb"}" is expanded as a single string.
If you want to set default parameters you might want to do this:
base=$(dirname -- "$0")
# test explicitly for no parameters, and set them.
if [ "$#" -eq 0 ]; then
set -- "$base/aaa" "$base/bbb"
fi
Then, the "$@" magically quoted parameter substitution can happen unabated:
touch -- "$@"
edited 35 mins ago
Stéphane Chazelas
300k54564916
answered 59 mins ago
glenn jackmanglenn jackman
50.6k570108
OP is using/bin/shso maybeif ((!$#)); thenorif [ $# -eq 0 ]; then?
– Jesse_b
54 mins ago
1
@Jesse_b It's a minor change and the rest works the same, but yes, that made it work for me
– millimoose
51 mins ago
(I like to stick to being dash-compatible if possible for scripts so as to not have to pull in bash into Docker images unnecessarily.)
– millimoose
45 mins ago
About that first sentence,set --; echo ${@:-default}; set -- a b; echo ${@:-default};works (i.e. printsdefaultand thena b) in all shells I tried. Though I don't think you should be able to give a list as a default value, the syntax only mentions a single word there.
– ilkkachu
38 mins ago
add a comment |
It appears you can't set default parameters in an expansion of ${@:-...}, and "${@:-"$base/aaa" "$base/bbb"}" is expanded as a single string.
If you want to set default parameters you might want to do this:
base=$(dirname -- "$0")
# test explicitly for no parameters, and set them.
if [ "$#" -eq 0 ]; then
set -- "$base/aaa" "$base/bbb"
fi
Then, the "$@" magically quoted parameter substitution can happen unabated:
touch -- "$@"
edited 35 mins ago
Stéphane Chazelas
300k54564916
answered 59 mins ago
glenn jackmanglenn jackman
50.6k570108
OP is using/bin/shso maybeif ((!$#)); thenorif [ $# -eq 0 ]; then?
– Jesse_b
54 mins ago
1
@Jesse_b It's a minor change and the rest works the same, but yes, that made it work for me
– millimoose
51 mins ago
(I like to stick to being dash-compatible if possible for scripts so as to not have to pull in bash into Docker images unnecessarily.)
– millimoose
45 mins ago
About that first sentence,set --; echo ${@:-default}; set -- a b; echo ${@:-default};works (i.e. printsdefaultand thena b) in all shells I tried. Though I don't think you should be able to give a list as a default value, the syntax only mentions a single word there.
– ilkkachu
38 mins ago
add a comment |
It appears you can't set default parameters in an expansion of ${@:-...}, and "${@:-"$base/aaa" "$base/bbb"}" is expanded as a single string.
If you want to set default parameters you might want to do this:
base=$(dirname -- "$0")
# test explicitly for no parameters, and set them.
if [ "$#" -eq 0 ]; then
set -- "$base/aaa" "$base/bbb"
fi
Then, the "$@" magically quoted parameter substitution can happen unabated:
touch -- "$@"
edited 35 mins ago
Stéphane Chazelas
300k54564916
answered 59 mins ago
glenn jackmanglenn jackman
50.6k570108
It appears you can't set default parameters in an expansion of ${@:-...}, and "${@:-"$base/aaa" "$base/bbb"}" is expanded as a single string.
If you want to set default parameters you might want to do this:
base=$(dirname -- "$0")
# test explicitly for no parameters, and set them.
if [ "$#" -eq 0 ]; then
set -- "$base/aaa" "$base/bbb"
fi
Then, the "$@" magically quoted parameter substitution can happen unabated:
touch -- "$@"
edited 35 mins ago
Stéphane Chazelas
300k54564916
answered 59 mins ago
glenn jackmanglenn jackman
50.6k570108
edited 35 mins ago
Stéphane Chazelas
300k54564916
edited 35 mins ago
Stéphane Chazelas
300k54564916
edited 35 mins ago
Stéphane Chazelas
300k54564916
300k54564916
answered 59 mins ago
glenn jackmanglenn jackman
50.6k570108
answered 59 mins ago
glenn jackmanglenn jackman
50.6k570108
answered 59 mins ago
glenn jackmanglenn jackman
50.6k570108
50.6k570108
OP is using/bin/shso maybeif ((!$#)); thenorif [ $# -eq 0 ]; then?
– Jesse_b
54 mins ago
1
@Jesse_b It's a minor change and the rest works the same, but yes, that made it work for me
– millimoose
51 mins ago
(I like to stick to being dash-compatible if possible for scripts so as to not have to pull in bash into Docker images unnecessarily.)
– millimoose
45 mins ago
About that first sentence,set --; echo ${@:-default}; set -- a b; echo ${@:-default};works (i.e. printsdefaultand thena b) in all shells I tried. Though I don't think you should be able to give a list as a default value, the syntax only mentions a single word there.
– ilkkachu
38 mins ago
add a comment |
OP is using/bin/shso maybeif ((!$#)); thenorif [ $# -eq 0 ]; then?
– Jesse_b
54 mins ago
1
@Jesse_b It's a minor change and the rest works the same, but yes, that made it work for me
– millimoose
51 mins ago
(I like to stick to being dash-compatible if possible for scripts so as to not have to pull in bash into Docker images unnecessarily.)
– millimoose
45 mins ago
About that first sentence,set --; echo ${@:-default}; set -- a b; echo ${@:-default};works (i.e. printsdefaultand thena b) in all shells I tried. Though I don't think you should be able to give a list as a default value, the syntax only mentions a single word there.
– ilkkachu
38 mins ago
OP is using
/bin/sh so maybe if ((!$#)); then or if [ $# -eq 0 ]; then?– Jesse_b
54 mins ago
OP is using
/bin/sh so maybe if ((!$#)); then or if [ $# -eq 0 ]; then?– Jesse_b
54 mins ago
1
1
@Jesse_b It's a minor change and the rest works the same, but yes, that made it work for me
– millimoose
51 mins ago
@Jesse_b It's a minor change and the rest works the same, but yes, that made it work for me
– millimoose
51 mins ago
(I like to stick to being dash-compatible if possible for scripts so as to not have to pull in bash into Docker images unnecessarily.)
– millimoose
45 mins ago
(I like to stick to being dash-compatible if possible for scripts so as to not have to pull in bash into Docker images unnecessarily.)
– millimoose
45 mins ago
About that first sentence,
set --; echo ${@:-default}; set -- a b; echo ${@:-default}; works (i.e. prints default and then a b) in all shells I tried. Though I don't think you should be able to give a list as a default value, the syntax only mentions a single word there.– ilkkachu
38 mins ago
About that first sentence,
set --; echo ${@:-default}; set -- a b; echo ${@:-default}; works (i.e. prints default and then a b) in all shells I tried. Though I don't think you should be able to give a list as a default value, the syntax only mentions a single word there.– ilkkachu
38 mins ago
add a comment |
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