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 4 hours ago
Gilles
530k12810631591
asked 4 hours ago
millimoosemillimoose
24315
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 4 hours ago
Gilles
530k12810631591
asked 4 hours ago
millimoosemillimoose
24315
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 4 hours ago
Gilles
530k12810631591
asked 4 hours ago
millimoosemillimoose
24315
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 4 hours ago
Gilles
530k12810631591
asked 4 hours ago
millimoosemillimoose
24315
edited 4 hours ago
Gilles
530k12810631591
asked 4 hours ago
millimoosemillimoose
24315
edited 4 hours ago
Gilles
530k12810631591
edited 4 hours ago
Gilles
530k12810631591
edited 4 hours ago
Gilles
530k12810631591
530k12810631591
asked 4 hours ago
millimoosemillimoose
24315
asked 4 hours ago
millimoosemillimoose
24315
asked 4 hours ago
millimoosemillimoose
24315
24315
add a comment |
add a comment |
2 Answers
2
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 4 hours ago
Stéphane Chazelas
300k54564916
answered 4 hours ago
glenn jackmanglenn jackman
50.6k570108
1
OP is using/bin/shso maybeif ((!$#)); thenorif [ $# -eq 0 ]; then?
– Jesse_b
4 hours ago
1
@Jesse_b It's a minor change and the rest works the same, but yes, that made it work for me
– millimoose
4 hours ago
1
(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
4 hours 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
4 hours ago
1
Sorry, but it is possible to use several parameters in a default expansion, but only with shells that have arrays. See my answer
– Isaac
3 hours ago
|
show 1 more comment
It IS possible to use several parameters in a default expansion ${@-...},
like this:
#!/bin/bash
base=$(dirname "$0")
arr=("$base/aaa" "$base/bbb")
touch "${@:-"${arr[@]}"}"
But only on shells that have arrays (ksh, zsh, bash, etc.).
edited 2 hours ago
Wildcard
22.7k962164
answered 3 hours ago
IsaacIsaac
11.4k11652
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
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 4 hours ago
Stéphane Chazelas
300k54564916
answered 4 hours ago
glenn jackmanglenn jackman
50.6k570108
1
OP is using/bin/shso maybeif ((!$#)); thenorif [ $# -eq 0 ]; then?
– Jesse_b
4 hours ago
1
@Jesse_b It's a minor change and the rest works the same, but yes, that made it work for me
– millimoose
4 hours ago
1
(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
4 hours 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
4 hours ago
1
Sorry, but it is possible to use several parameters in a default expansion, but only with shells that have arrays. See my answer
– Isaac
3 hours ago
|
show 1 more 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 4 hours ago
Stéphane Chazelas
300k54564916
answered 4 hours ago
glenn jackmanglenn jackman
50.6k570108
1
OP is using/bin/shso maybeif ((!$#)); thenorif [ $# -eq 0 ]; then?
– Jesse_b
4 hours ago
1
@Jesse_b It's a minor change and the rest works the same, but yes, that made it work for me
– millimoose
4 hours ago
1
(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
4 hours 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
4 hours ago
1
Sorry, but it is possible to use several parameters in a default expansion, but only with shells that have arrays. See my answer
– Isaac
3 hours ago
|
show 1 more 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 4 hours ago
Stéphane Chazelas
300k54564916
answered 4 hours 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 4 hours ago
Stéphane Chazelas
300k54564916
answered 4 hours ago
glenn jackmanglenn jackman
50.6k570108
edited 4 hours ago
Stéphane Chazelas
300k54564916
edited 4 hours ago
Stéphane Chazelas
300k54564916
edited 4 hours ago
Stéphane Chazelas
300k54564916
300k54564916
answered 4 hours ago
glenn jackmanglenn jackman
50.6k570108
answered 4 hours ago
glenn jackmanglenn jackman
50.6k570108
answered 4 hours ago
glenn jackmanglenn jackman
50.6k570108
50.6k570108
1
OP is using/bin/shso maybeif ((!$#)); thenorif [ $# -eq 0 ]; then?
– Jesse_b
4 hours ago
1
@Jesse_b It's a minor change and the rest works the same, but yes, that made it work for me
– millimoose
4 hours ago
1
(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
4 hours ago
About that first sentence,set --; echo ${@:-default}; set -- a b; echo ${@:-default};works (i.e. printsdefaultand thena b) in all shells I tried. Though I don't think you should be able to give a list as a default value, the syntax only mentions a single word there.
– ilkkachu
4 hours ago
1
Sorry, but it is possible to use several parameters in a default expansion, but only with shells that have arrays. See my answer
– Isaac
3 hours ago
|
show 1 more comment
1
OP is using/bin/shso maybeif ((!$#)); thenorif [ $# -eq 0 ]; then?
– Jesse_b
4 hours ago
1
@Jesse_b It's a minor change and the rest works the same, but yes, that made it work for me
– millimoose
4 hours ago
1
(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
4 hours ago
About that first sentence,set --; echo ${@:-default}; set -- a b; echo ${@:-default};works (i.e. printsdefaultand thena b) in all shells I tried. Though I don't think you should be able to give a list as a default value, the syntax only mentions a single word there.
– ilkkachu
4 hours ago
1
Sorry, but it is possible to use several parameters in a default expansion, but only with shells that have arrays. See my answer
– Isaac
3 hours ago
1
1
OP is using
/bin/sh so maybe if ((!$#)); then or if [ $# -eq 0 ]; then?– Jesse_b
4 hours ago
OP is using
/bin/sh so maybe if ((!$#)); then or if [ $# -eq 0 ]; then?– Jesse_b
4 hours 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
4 hours ago
@Jesse_b It's a minor change and the rest works the same, but yes, that made it work for me
– millimoose
4 hours ago
1
1
(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
4 hours 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
4 hours 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
4 hours 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
4 hours ago
1
1
Sorry, but it is possible to use several parameters in a default expansion, but only with shells that have arrays. See my answer
– Isaac
3 hours ago
Sorry, but it is possible to use several parameters in a default expansion, but only with shells that have arrays. See my answer
– Isaac
3 hours ago
|
show 1 more comment
It IS possible to use several parameters in a default expansion ${@-...},
like this:
#!/bin/bash
base=$(dirname "$0")
arr=("$base/aaa" "$base/bbb")
touch "${@:-"${arr[@]}"}"
But only on shells that have arrays (ksh, zsh, bash, etc.).
edited 2 hours ago
Wildcard
22.7k962164
answered 3 hours ago
IsaacIsaac
11.4k11652
add a comment |
It IS possible to use several parameters in a default expansion ${@-...},
like this:
#!/bin/bash
base=$(dirname "$0")
arr=("$base/aaa" "$base/bbb")
touch "${@:-"${arr[@]}"}"
But only on shells that have arrays (ksh, zsh, bash, etc.).
edited 2 hours ago
Wildcard
22.7k962164
answered 3 hours ago
IsaacIsaac
11.4k11652
add a comment |
It IS possible to use several parameters in a default expansion ${@-...},
like this:
#!/bin/bash
base=$(dirname "$0")
arr=("$base/aaa" "$base/bbb")
touch "${@:-"${arr[@]}"}"
But only on shells that have arrays (ksh, zsh, bash, etc.).
edited 2 hours ago
Wildcard
22.7k962164
answered 3 hours ago
IsaacIsaac
11.4k11652
It IS possible to use several parameters in a default expansion ${@-...},
like this:
#!/bin/bash
base=$(dirname "$0")
arr=("$base/aaa" "$base/bbb")
touch "${@:-"${arr[@]}"}"
But only on shells that have arrays (ksh, zsh, bash, etc.).
edited 2 hours ago
Wildcard
22.7k962164
answered 3 hours ago
IsaacIsaac
11.4k11652
edited 2 hours ago
Wildcard
22.7k962164
edited 2 hours ago
Wildcard
22.7k962164
edited 2 hours ago
Wildcard
22.7k962164
22.7k962164
answered 3 hours ago
IsaacIsaac
11.4k11652
answered 3 hours ago
IsaacIsaac
11.4k11652
answered 3 hours ago
IsaacIsaac
11.4k11652
11.4k11652
add a comment |
add a comment |
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