Shell: Is it possible to give a string as a file to a command?
1
Suppose we have a command,
eval-some-language —-path=<filename>
And we want to do something like this:
eval-some-language —-path=“say hello world!
exit 3”
I think the following solution might work for one file, and if stdin is not used for sth else:
eval-some-language —-path=“/dev/stdin” <<<“say hello ...”
Does this work with all commands? How portable is it? (macOS?)
And is there any other ways to do this?
Update: Both my solution, the accepted answer, and zsh’s =() don’t work if the file needs to be executable. :(
linux bash filesystems zsh command-substitution
asked Dec 16 at 19:09
HappyFace
31811
add a comment |
1
Suppose we have a command,
eval-some-language —-path=<filename>
And we want to do something like this:
eval-some-language —-path=“say hello world!
exit 3”
I think the following solution might work for one file, and if stdin is not used for sth else:
eval-some-language —-path=“/dev/stdin” <<<“say hello ...”
Does this work with all commands? How portable is it? (macOS?)
And is there any other ways to do this?
Update: Both my solution, the accepted answer, and zsh’s =() don’t work if the file needs to be executable. :(
linux bash filesystems zsh command-substitution
asked Dec 16 at 19:09
HappyFace
31811
1
This is an XY problem. Why not ask what you want to accomplish? What do you want to do to each download?
– Dani_l
Dec 16 at 20:55
add a comment |
1
1
1
Suppose we have a command,
eval-some-language —-path=<filename>
And we want to do something like this:
eval-some-language —-path=“say hello world!
exit 3”
I think the following solution might work for one file, and if stdin is not used for sth else:
eval-some-language —-path=“/dev/stdin” <<<“say hello ...”
Does this work with all commands? How portable is it? (macOS?)
And is there any other ways to do this?
Update: Both my solution, the accepted answer, and zsh’s =() don’t work if the file needs to be executable. :(
linux bash filesystems zsh command-substitution
asked Dec 16 at 19:09
HappyFace
31811
Suppose we have a command,
eval-some-language —-path=<filename>
And we want to do something like this:
eval-some-language —-path=“say hello world!
exit 3”
I think the following solution might work for one file, and if stdin is not used for sth else:
eval-some-language —-path=“/dev/stdin” <<<“say hello ...”
Does this work with all commands? How portable is it? (macOS?)
And is there any other ways to do this?
Update: Both my solution, the accepted answer, and zsh’s =() don’t work if the file needs to be executable. :(
linux bash filesystems zsh command-substitution
linux bash filesystems zsh command-substitution
asked Dec 16 at 19:09
HappyFace
31811
asked Dec 16 at 19:09
HappyFace
31811
edited Dec 16 at 19:46
asked Dec 16 at 19:09
HappyFace
31811
asked Dec 16 at 19:09
HappyFace
31811
asked Dec 16 at 19:09
HappyFace
31811
31811
1
This is an XY problem. Why not ask what you want to accomplish? What do you want to do to each download?
– Dani_l
Dec 16 at 20:55
add a comment |
1
This is an XY problem. Why not ask what you want to accomplish? What do you want to do to each download?
– Dani_l
Dec 16 at 20:55
1
1
This is an XY problem. Why not ask what you want to accomplish? What do you want to do to each download?
– Dani_l
Dec 16 at 20:55
This is an XY problem. Why not ask what you want to accomplish? What do you want to do to each download?
– Dani_l
Dec 16 at 20:55
add a comment |
1 Answer
1
active
oldest
votes
1
Try this:
eval-some-language --path=<(echo "hello world")
<() will generate a file descriptor, tied to the output of the command and pass it as /dev/fd/xxx. E.g:
$ echo <(echo aaa)
/dev/fd/63
$ echo <(echo test) <(echo second test)
/dev/fd/63 /dev/fd/62
For slightly more information see the "Process Substittution" section in man bash
answered Dec 16 at 19:21
V13
2,799613
Sadly it again gave me an error saying the file isn’t executable. :(
– HappyFace
Dec 16 at 19:24
That's probably unrelated. What exactly did you run?
– V13
Dec 16 at 19:25
aria2c “some-url” —on-download-complete <(echo “touch nnn6”)and the — is typed wrongly on my iPad.
– HappyFace
Dec 16 at 19:28
1
--on-download-complete requires an executable script to execute. That's way different than just a file and certainly doesn't work with your solution either. You need an actual file if you want to execute it. Your best solution is to generate a temporary file with mktemp, make it executable and pass that as a parameter.
– V13
Dec 16 at 19:41
1
@jimmij, they seem to want an executable file that their program executes once it downloads something. I don't think that can ever be possible because executing a program with execve() will require a real file with executable permissions.
– V13
Dec 16 at 20:02
add a comment |
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1 Answer
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active
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1
Try this:
eval-some-language --path=<(echo "hello world")
<() will generate a file descriptor, tied to the output of the command and pass it as /dev/fd/xxx. E.g:
$ echo <(echo aaa)
/dev/fd/63
$ echo <(echo test) <(echo second test)
/dev/fd/63 /dev/fd/62
For slightly more information see the "Process Substittution" section in man bash
answered Dec 16 at 19:21
V13
2,799613
Sadly it again gave me an error saying the file isn’t executable. :(
– HappyFace
Dec 16 at 19:24
That's probably unrelated. What exactly did you run?
– V13
Dec 16 at 19:25
aria2c “some-url” —on-download-complete <(echo “touch nnn6”)and the — is typed wrongly on my iPad.
– HappyFace
Dec 16 at 19:28
1
--on-download-complete requires an executable script to execute. That's way different than just a file and certainly doesn't work with your solution either. You need an actual file if you want to execute it. Your best solution is to generate a temporary file with mktemp, make it executable and pass that as a parameter.
– V13
Dec 16 at 19:41
1
@jimmij, they seem to want an executable file that their program executes once it downloads something. I don't think that can ever be possible because executing a program with execve() will require a real file with executable permissions.
– V13
Dec 16 at 20:02
add a comment |
1
Try this:
eval-some-language --path=<(echo "hello world")
<() will generate a file descriptor, tied to the output of the command and pass it as /dev/fd/xxx. E.g:
$ echo <(echo aaa)
/dev/fd/63
$ echo <(echo test) <(echo second test)
/dev/fd/63 /dev/fd/62
For slightly more information see the "Process Substittution" section in man bash
answered Dec 16 at 19:21
V13
2,799613
Sadly it again gave me an error saying the file isn’t executable. :(
– HappyFace
Dec 16 at 19:24
That's probably unrelated. What exactly did you run?
– V13
Dec 16 at 19:25
aria2c “some-url” —on-download-complete <(echo “touch nnn6”)and the — is typed wrongly on my iPad.
– HappyFace
Dec 16 at 19:28
1
--on-download-complete requires an executable script to execute. That's way different than just a file and certainly doesn't work with your solution either. You need an actual file if you want to execute it. Your best solution is to generate a temporary file with mktemp, make it executable and pass that as a parameter.
– V13
Dec 16 at 19:41
1
@jimmij, they seem to want an executable file that their program executes once it downloads something. I don't think that can ever be possible because executing a program with execve() will require a real file with executable permissions.
– V13
Dec 16 at 20:02
add a comment |
1
1
1
Try this:
eval-some-language --path=<(echo "hello world")
<() will generate a file descriptor, tied to the output of the command and pass it as /dev/fd/xxx. E.g:
$ echo <(echo aaa)
/dev/fd/63
$ echo <(echo test) <(echo second test)
/dev/fd/63 /dev/fd/62
For slightly more information see the "Process Substittution" section in man bash
answered Dec 16 at 19:21
V13
2,799613
Try this:
eval-some-language --path=<(echo "hello world")
<() will generate a file descriptor, tied to the output of the command and pass it as /dev/fd/xxx. E.g:
$ echo <(echo aaa)
/dev/fd/63
$ echo <(echo test) <(echo second test)
/dev/fd/63 /dev/fd/62
For slightly more information see the "Process Substittution" section in man bash
answered Dec 16 at 19:21
V13
2,799613
answered Dec 16 at 19:21
V13
2,799613
answered Dec 16 at 19:21
V13
2,799613
answered Dec 16 at 19:21
V13
2,799613
2,799613
Sadly it again gave me an error saying the file isn’t executable. :(
– HappyFace
Dec 16 at 19:24
That's probably unrelated. What exactly did you run?
– V13
Dec 16 at 19:25
aria2c “some-url” —on-download-complete <(echo “touch nnn6”)and the — is typed wrongly on my iPad.
– HappyFace
Dec 16 at 19:28
1
--on-download-complete requires an executable script to execute. That's way different than just a file and certainly doesn't work with your solution either. You need an actual file if you want to execute it. Your best solution is to generate a temporary file with mktemp, make it executable and pass that as a parameter.
– V13
Dec 16 at 19:41
1
@jimmij, they seem to want an executable file that their program executes once it downloads something. I don't think that can ever be possible because executing a program with execve() will require a real file with executable permissions.
– V13
Dec 16 at 20:02
add a comment |
Sadly it again gave me an error saying the file isn’t executable. :(
– HappyFace
Dec 16 at 19:24
That's probably unrelated. What exactly did you run?
– V13
Dec 16 at 19:25
aria2c “some-url” —on-download-complete <(echo “touch nnn6”)and the — is typed wrongly on my iPad.
– HappyFace
Dec 16 at 19:28
1
--on-download-complete requires an executable script to execute. That's way different than just a file and certainly doesn't work with your solution either. You need an actual file if you want to execute it. Your best solution is to generate a temporary file with mktemp, make it executable and pass that as a parameter.
– V13
Dec 16 at 19:41
1
@jimmij, they seem to want an executable file that their program executes once it downloads something. I don't think that can ever be possible because executing a program with execve() will require a real file with executable permissions.
– V13
Dec 16 at 20:02
Sadly it again gave me an error saying the file isn’t executable. :(
– HappyFace
Dec 16 at 19:24
Sadly it again gave me an error saying the file isn’t executable. :(
– HappyFace
Dec 16 at 19:24
That's probably unrelated. What exactly did you run?
– V13
Dec 16 at 19:25
That's probably unrelated. What exactly did you run?
– V13
Dec 16 at 19:25
aria2c “some-url” —on-download-complete <(echo “touch nnn6”) and the — is typed wrongly on my iPad.– HappyFace
Dec 16 at 19:28
aria2c “some-url” —on-download-complete <(echo “touch nnn6”) and the — is typed wrongly on my iPad.– HappyFace
Dec 16 at 19:28
1
1
--on-download-complete requires an executable script to execute. That's way different than just a file and certainly doesn't work with your solution either. You need an actual file if you want to execute it. Your best solution is to generate a temporary file with mktemp, make it executable and pass that as a parameter.
– V13
Dec 16 at 19:41
--on-download-complete requires an executable script to execute. That's way different than just a file and certainly doesn't work with your solution either. You need an actual file if you want to execute it. Your best solution is to generate a temporary file with mktemp, make it executable and pass that as a parameter.
– V13
Dec 16 at 19:41
1
1
@jimmij, they seem to want an executable file that their program executes once it downloads something. I don't think that can ever be possible because executing a program with execve() will require a real file with executable permissions.
– V13
Dec 16 at 20:02
@jimmij, they seem to want an executable file that their program executes once it downloads something. I don't think that can ever be possible because executing a program with execve() will require a real file with executable permissions.
– V13
Dec 16 at 20:02
add a comment |
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1
This is an XY problem. Why not ask what you want to accomplish? What do you want to do to each download?
– Dani_l
Dec 16 at 20:55