Is such redirection “|>†just an error or it means something?
Clash Royale CLAN TAG#URR8PPP
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I typed it by mistake but bash didn't print any errors (but created an empty file) so I thought maybe it actually means something ?
(e.g. date |> tmp.txt)
bash io-redirection
asked Sep 25 at 8:20
Bdimych2 Bdimych2
462
add a comment |Â
up vote
8
down vote
favorite
I typed it by mistake but bash didn't print any errors (but created an empty file) so I thought maybe it actually means something ?
(e.g. date |> tmp.txt)
bash io-redirection
asked Sep 25 at 8:20
Bdimych2 Bdimych2
462
1
Are you sure the command isn’t of the formdate |> tmp.txt cmd2? Because that changes the answer.
– Konrad Rudolph
Sep 25 at 13:26
add a comment |Â
up vote
8
down vote
favorite
up vote
8
down vote
favorite
I typed it by mistake but bash didn't print any errors (but created an empty file) so I thought maybe it actually means something ?
(e.g. date |> tmp.txt)
bash io-redirection
asked Sep 25 at 8:20
Bdimych2 Bdimych2
462
I typed it by mistake but bash didn't print any errors (but created an empty file) so I thought maybe it actually means something ?
(e.g. date |> tmp.txt)
bash io-redirection
bash io-redirection
asked Sep 25 at 8:20
Bdimych2 Bdimych2
462
asked Sep 25 at 8:20
Bdimych2 Bdimych2
462
asked Sep 25 at 8:20
Bdimych2 Bdimych2
462
asked Sep 25 at 8:20
Bdimych2 Bdimych2
462
asked Sep 25 at 8:20
Bdimych2 Bdimych2
462
462
1
Are you sure the command isn’t of the formdate |> tmp.txt cmd2? Because that changes the answer.
– Konrad Rudolph
Sep 25 at 13:26
add a comment |Â
1
Are you sure the command isn’t of the formdate |> tmp.txt cmd2? Because that changes the answer.
– Konrad Rudolph
Sep 25 at 13:26
1
1
Are you sure the command isn’t of the form
date |> tmp.txt cmd2? Because that changes the answer.– Konrad Rudolph
Sep 25 at 13:26
Are you sure the command isn’t of the form
date |> tmp.txt cmd2? Because that changes the answer.– Konrad Rudolph
Sep 25 at 13:26
add a comment |Â
2 Answers
2
active
oldest
votes
up vote
17
down vote
That seems to be just a pipeline where the second part is an empty command, only containing the redirection. Writing it as date | >file might make it easier to interpret. The empty command doesn't do anything but process the redirection, creating the file.
date >| file on the other hand would act as an override for the noclobber shell option, which prevents the regular > from overwriting existing files.
$ touch foo; set -o noclobber
$ date > foo
bash: foo: cannot overwrite existing file
$ date >| foo # works
edited Sep 29 at 13:11
Jeff Schaller
33.3k850112
answered Sep 25 at 8:26
ilkkachu
52.5k679145
add a comment |Â
up vote
1
down vote
Yes, it will not throw error because for bash > file means redirect to a file named file. As in your case there is nothing to redirect to file, bash will just create a file name file with nothing in it.
[bd@centos-6.5 my-tests]$ date | > my_file
[bd@centos-6.5 my-tests]$ cat my_file
[bd@centos-6.5 my-tests]$
answered Sep 25 at 9:07
Bhagyesh Dudhediya
316314
Funny. Zsh has a different behavior: after the command,my_filecontains the output ofdate.
– Najib Idrissi
Sep 25 at 9:28
12
@NajibIdrissi, inzsh, when there are only redirections and no command,zshruns the$NULLCMDcommand (catby default) or$READNULLCMD(a pager by default) if there are only input redirections.
– Stéphane Chazelas
Sep 25 at 9:34
add a comment |Â
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
17
down vote
That seems to be just a pipeline where the second part is an empty command, only containing the redirection. Writing it as date | >file might make it easier to interpret. The empty command doesn't do anything but process the redirection, creating the file.
date >| file on the other hand would act as an override for the noclobber shell option, which prevents the regular > from overwriting existing files.
$ touch foo; set -o noclobber
$ date > foo
bash: foo: cannot overwrite existing file
$ date >| foo # works
edited Sep 29 at 13:11
Jeff Schaller
33.3k850112
answered Sep 25 at 8:26
ilkkachu
52.5k679145
add a comment |Â
up vote
17
down vote
That seems to be just a pipeline where the second part is an empty command, only containing the redirection. Writing it as date | >file might make it easier to interpret. The empty command doesn't do anything but process the redirection, creating the file.
date >| file on the other hand would act as an override for the noclobber shell option, which prevents the regular > from overwriting existing files.
$ touch foo; set -o noclobber
$ date > foo
bash: foo: cannot overwrite existing file
$ date >| foo # works
edited Sep 29 at 13:11
Jeff Schaller
33.3k850112
answered Sep 25 at 8:26
ilkkachu
52.5k679145
add a comment |Â
up vote
17
down vote
up vote
17
down vote
That seems to be just a pipeline where the second part is an empty command, only containing the redirection. Writing it as date | >file might make it easier to interpret. The empty command doesn't do anything but process the redirection, creating the file.
date >| file on the other hand would act as an override for the noclobber shell option, which prevents the regular > from overwriting existing files.
$ touch foo; set -o noclobber
$ date > foo
bash: foo: cannot overwrite existing file
$ date >| foo # works
edited Sep 29 at 13:11
Jeff Schaller
33.3k850112
answered Sep 25 at 8:26
ilkkachu
52.5k679145
That seems to be just a pipeline where the second part is an empty command, only containing the redirection. Writing it as date | >file might make it easier to interpret. The empty command doesn't do anything but process the redirection, creating the file.
date >| file on the other hand would act as an override for the noclobber shell option, which prevents the regular > from overwriting existing files.
$ touch foo; set -o noclobber
$ date > foo
bash: foo: cannot overwrite existing file
$ date >| foo # works
edited Sep 29 at 13:11
Jeff Schaller
33.3k850112
answered Sep 25 at 8:26
ilkkachu
52.5k679145
edited Sep 29 at 13:11
Jeff Schaller
33.3k850112
edited Sep 29 at 13:11
Jeff Schaller
33.3k850112
edited Sep 29 at 13:11
Jeff Schaller
33.3k850112
33.3k850112
answered Sep 25 at 8:26
ilkkachu
52.5k679145
answered Sep 25 at 8:26
ilkkachu
52.5k679145
answered Sep 25 at 8:26
ilkkachu
52.5k679145
52.5k679145
add a comment |Â
add a comment |Â
up vote
1
down vote
Yes, it will not throw error because for bash > file means redirect to a file named file. As in your case there is nothing to redirect to file, bash will just create a file name file with nothing in it.
[bd@centos-6.5 my-tests]$ date | > my_file
[bd@centos-6.5 my-tests]$ cat my_file
[bd@centos-6.5 my-tests]$
answered Sep 25 at 9:07
Bhagyesh Dudhediya
316314
Funny. Zsh has a different behavior: after the command,my_filecontains the output ofdate.
– Najib Idrissi
Sep 25 at 9:28
12
@NajibIdrissi, inzsh, when there are only redirections and no command,zshruns the$NULLCMDcommand (catby default) or$READNULLCMD(a pager by default) if there are only input redirections.
– Stéphane Chazelas
Sep 25 at 9:34
add a comment |Â
up vote
1
down vote
Yes, it will not throw error because for bash > file means redirect to a file named file. As in your case there is nothing to redirect to file, bash will just create a file name file with nothing in it.
[bd@centos-6.5 my-tests]$ date | > my_file
[bd@centos-6.5 my-tests]$ cat my_file
[bd@centos-6.5 my-tests]$
answered Sep 25 at 9:07
Bhagyesh Dudhediya
316314
Funny. Zsh has a different behavior: after the command,my_filecontains the output ofdate.
– Najib Idrissi
Sep 25 at 9:28
12
@NajibIdrissi, inzsh, when there are only redirections and no command,zshruns the$NULLCMDcommand (catby default) or$READNULLCMD(a pager by default) if there are only input redirections.
– Stéphane Chazelas
Sep 25 at 9:34
add a comment |Â
up vote
1
down vote
up vote
1
down vote
Yes, it will not throw error because for bash > file means redirect to a file named file. As in your case there is nothing to redirect to file, bash will just create a file name file with nothing in it.
[bd@centos-6.5 my-tests]$ date | > my_file
[bd@centos-6.5 my-tests]$ cat my_file
[bd@centos-6.5 my-tests]$
answered Sep 25 at 9:07
Bhagyesh Dudhediya
316314
Yes, it will not throw error because for bash > file means redirect to a file named file. As in your case there is nothing to redirect to file, bash will just create a file name file with nothing in it.
[bd@centos-6.5 my-tests]$ date | > my_file
[bd@centos-6.5 my-tests]$ cat my_file
[bd@centos-6.5 my-tests]$
answered Sep 25 at 9:07
Bhagyesh Dudhediya
316314
edited Sep 25 at 9:14
answered Sep 25 at 9:07
Bhagyesh Dudhediya
316314
answered Sep 25 at 9:07
Bhagyesh Dudhediya
316314
answered Sep 25 at 9:07
Bhagyesh Dudhediya
316314
316314
Funny. Zsh has a different behavior: after the command,my_filecontains the output ofdate.
– Najib Idrissi
Sep 25 at 9:28
12
@NajibIdrissi, inzsh, when there are only redirections and no command,zshruns the$NULLCMDcommand (catby default) or$READNULLCMD(a pager by default) if there are only input redirections.
– Stéphane Chazelas
Sep 25 at 9:34
add a comment |Â
Funny. Zsh has a different behavior: after the command,my_filecontains the output ofdate.
– Najib Idrissi
Sep 25 at 9:28
12
@NajibIdrissi, inzsh, when there are only redirections and no command,zshruns the$NULLCMDcommand (catby default) or$READNULLCMD(a pager by default) if there are only input redirections.
– Stéphane Chazelas
Sep 25 at 9:34
Funny. Zsh has a different behavior: after the command,
my_file contains the output of date.– Najib Idrissi
Sep 25 at 9:28
Funny. Zsh has a different behavior: after the command,
my_file contains the output of date.– Najib Idrissi
Sep 25 at 9:28
12
12
@NajibIdrissi, in
zsh, when there are only redirections and no command, zsh runs the $NULLCMD command (cat by default) or $READNULLCMD (a pager by default) if there are only input redirections.– Stéphane Chazelas
Sep 25 at 9:34
@NajibIdrissi, in
zsh, when there are only redirections and no command, zsh runs the $NULLCMD command (cat by default) or $READNULLCMD (a pager by default) if there are only input redirections.– Stéphane Chazelas
Sep 25 at 9:34
add a comment |Â
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1
Are you sure the command isn’t of the form
date |> tmp.txt cmd2? Because that changes the answer.– Konrad Rudolph
Sep 25 at 13:26