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 14 hours ago
Gilles
530k12810631591
asked 14 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 14 hours ago
Gilles
530k12810631591
asked 14 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 14 hours ago
Gilles
530k12810631591
asked 14 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 14 hours ago
Gilles
530k12810631591
asked 14 hours ago
millimoosemillimoose
24315
edited 14 hours ago
Gilles
530k12810631591
asked 14 hours ago
millimoosemillimoose
24315
edited 14 hours ago
Gilles
530k12810631591
edited 14 hours ago
Gilles
530k12810631591
edited 14 hours ago
Gilles
530k12810631591
530k12810631591
asked 14 hours ago
millimoosemillimoose
24315
asked 14 hours ago
millimoosemillimoose
24315
asked 14 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 14 hours ago
Stéphane Chazelas
300k55564916
answered 14 hours ago
glenn jackmanglenn jackman
50.6k571109
1
@Jesse_b It's a minor change and the rest works the same, but yes, that made it work for me
– millimoose
14 hours ago
2
(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
14 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
14 hours ago
2
Sorry, but it is possible to use several parameters in a default expansion, but only with shells that have arrays. See my answer
– Isaac
13 hours ago
@ilkkachu - I mean in the context of my question I understood that sentence as “it’s impossible to do that and have it expand as OP wants”
– millimoose
12 hours ago
|
show 3 more comments
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 12 hours ago
Wildcard
22.7k962164
answered 13 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 14 hours ago
Stéphane Chazelas
300k55564916
answered 14 hours ago
glenn jackmanglenn jackman
50.6k571109
1
@Jesse_b It's a minor change and the rest works the same, but yes, that made it work for me
– millimoose
14 hours ago
2
(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
14 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
14 hours ago
2
Sorry, but it is possible to use several parameters in a default expansion, but only with shells that have arrays. See my answer
– Isaac
13 hours ago
@ilkkachu - I mean in the context of my question I understood that sentence as “it’s impossible to do that and have it expand as OP wants”
– millimoose
12 hours ago
|
show 3 more comments
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 14 hours ago
Stéphane Chazelas
300k55564916
answered 14 hours ago
glenn jackmanglenn jackman
50.6k571109
1
@Jesse_b It's a minor change and the rest works the same, but yes, that made it work for me
– millimoose
14 hours ago
2
(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
14 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
14 hours ago
2
Sorry, but it is possible to use several parameters in a default expansion, but only with shells that have arrays. See my answer
– Isaac
13 hours ago
@ilkkachu - I mean in the context of my question I understood that sentence as “it’s impossible to do that and have it expand as OP wants”
– millimoose
12 hours ago
|
show 3 more comments
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 14 hours ago
Stéphane Chazelas
300k55564916
answered 14 hours ago
glenn jackmanglenn jackman
50.6k571109
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 14 hours ago
Stéphane Chazelas
300k55564916
answered 14 hours ago
glenn jackmanglenn jackman
50.6k571109
edited 14 hours ago
Stéphane Chazelas
300k55564916
edited 14 hours ago
Stéphane Chazelas
300k55564916
edited 14 hours ago
Stéphane Chazelas
300k55564916
300k55564916
answered 14 hours ago
glenn jackmanglenn jackman
50.6k571109
answered 14 hours ago
glenn jackmanglenn jackman
50.6k571109
answered 14 hours ago
glenn jackmanglenn jackman
50.6k571109
50.6k571109
1
@Jesse_b It's a minor change and the rest works the same, but yes, that made it work for me
– millimoose
14 hours ago
2
(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
14 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
14 hours ago
2
Sorry, but it is possible to use several parameters in a default expansion, but only with shells that have arrays. See my answer
– Isaac
13 hours ago
@ilkkachu - I mean in the context of my question I understood that sentence as “it’s impossible to do that and have it expand as OP wants”
– millimoose
12 hours ago
|
show 3 more comments
1
@Jesse_b It's a minor change and the rest works the same, but yes, that made it work for me
– millimoose
14 hours ago
2
(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
14 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
14 hours ago
2
Sorry, but it is possible to use several parameters in a default expansion, but only with shells that have arrays. See my answer
– Isaac
13 hours ago
@ilkkachu - I mean in the context of my question I understood that sentence as “it’s impossible to do that and have it expand as OP wants”
– millimoose
12 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
14 hours ago
@Jesse_b It's a minor change and the rest works the same, but yes, that made it work for me
– millimoose
14 hours ago
2
2
(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
14 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
14 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
14 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
14 hours ago
2
2
Sorry, but it is possible to use several parameters in a default expansion, but only with shells that have arrays. See my answer
– Isaac
13 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
13 hours ago
@ilkkachu - I mean in the context of my question I understood that sentence as “it’s impossible to do that and have it expand as OP wants”
– millimoose
12 hours ago
@ilkkachu - I mean in the context of my question I understood that sentence as “it’s impossible to do that and have it expand as OP wants”
– millimoose
12 hours ago
|
show 3 more comments
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 12 hours ago
Wildcard
22.7k962164
answered 13 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 12 hours ago
Wildcard
22.7k962164
answered 13 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 12 hours ago
Wildcard
22.7k962164
answered 13 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 12 hours ago
Wildcard
22.7k962164
answered 13 hours ago
IsaacIsaac
11.4k11652
edited 12 hours ago
Wildcard
22.7k962164
edited 12 hours ago
Wildcard
22.7k962164
edited 12 hours ago
Wildcard
22.7k962164
22.7k962164
answered 13 hours ago
IsaacIsaac
11.4k11652
answered 13 hours ago
IsaacIsaac
11.4k11652
answered 13 hours ago
IsaacIsaac
11.4k11652
11.4k11652
add a comment |
add a comment |
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