SSH output isn't line buffered?
I'm running a script on a remote machine like this:
ssh $host "pip install -r /path/to/requirements.txt"
But the output isn't line buffered; instead of seeing one line returned at a time, all the lines (~10) are all printed at once as the connection terminates.
What's up with this? Is there any way to force them to be line buffered?
(also, to state the obvious: when I ssh into $host and run the command “manually”, the output is line buffered, as expected)
ssh
asked Oct 3 '11 at 2:48
David WoleverDavid Wolever
1,30421214
add a comment |
I'm running a script on a remote machine like this:
ssh $host "pip install -r /path/to/requirements.txt"
But the output isn't line buffered; instead of seeing one line returned at a time, all the lines (~10) are all printed at once as the connection terminates.
What's up with this? Is there any way to force them to be line buffered?
(also, to state the obvious: when I ssh into $host and run the command “manually”, the output is line buffered, as expected)
ssh
asked Oct 3 '11 at 2:48
David WoleverDavid Wolever
1,30421214
add a comment |
I'm running a script on a remote machine like this:
ssh $host "pip install -r /path/to/requirements.txt"
But the output isn't line buffered; instead of seeing one line returned at a time, all the lines (~10) are all printed at once as the connection terminates.
What's up with this? Is there any way to force them to be line buffered?
(also, to state the obvious: when I ssh into $host and run the command “manually”, the output is line buffered, as expected)
ssh
asked Oct 3 '11 at 2:48
David WoleverDavid Wolever
1,30421214
I'm running a script on a remote machine like this:
ssh $host "pip install -r /path/to/requirements.txt"
But the output isn't line buffered; instead of seeing one line returned at a time, all the lines (~10) are all printed at once as the connection terminates.
What's up with this? Is there any way to force them to be line buffered?
(also, to state the obvious: when I ssh into $host and run the command “manually”, the output is line buffered, as expected)
ssh
ssh
asked Oct 3 '11 at 2:48
David WoleverDavid Wolever
1,30421214
asked Oct 3 '11 at 2:48
David WoleverDavid Wolever
1,30421214
asked Oct 3 '11 at 2:48
David WoleverDavid Wolever
1,30421214
asked Oct 3 '11 at 2:48
David WoleverDavid Wolever
1,30421214
asked Oct 3 '11 at 2:48
David WoleverDavid Wolever
1,30421214
1,30421214
add a comment |
add a comment |
3 Answers
3
active
oldest
votes
Use ssh -t ... to force a pseudo-tty allocation (which is what you get when you log in normally via ssh.)
answered Oct 3 '11 at 2:55
Ryan FoxRyan Fox
53654
didn't help, unfortunately. This also might be problem with MTU, but neither of it helped
– Nick Roz
Sep 9 '16 at 23:48
See Magnus' comment below ref using-tt- that worked for me when -t didn't.
– Tom Dalton
Mar 26 '18 at 13:35
add a comment |
To expand a little bit on Ryan Fox's answer:
Many programs (most? - it's the default for any C program) line-buffer stdout when they're talking to a terminal, but fully buffer it otherwise. (The C standard specifies that stdout is initially fully buffered when it "can be determined not to refer to an interactive device".)
So what you're seeing is that the output of the program you're running remotely (as given to stdout) isn't line-buffered; ssh is just passing through what it gets when it gets it. (I think ssh actually does no buffering at all on its output - that would be the least magical way to make sure that the user sees what the remote program intended.)
edited Oct 3 '11 at 10:59
David Wolever
1,30421214
answered Oct 3 '11 at 3:25
Dave VanderviesDave Vandervies
23112
An anonymous user suggests that stdout is fully buffered, not line buffered
– Michael Mrozek♦
Oct 3 '11 at 3:53
Dave Vandervies has told me out-of-band that he was the one who made the edit, and that it is correct (ie, stdout is initially fully buffered, not line buffered).
– David Wolever
Oct 3 '11 at 6:05
add a comment |
To expand even more on Ryan Fox's answer, ssh -t didn't work for me either, but ssh -tt did. See the ssh man page about -t:
Multiple -t options force tty allocation, even if ssh has no local tty
edited 6 mins ago
PRY
2,55831026
answered Nov 23 '17 at 8:06
Magnus BergMagnus Berg
5111
add a comment |
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3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
Use ssh -t ... to force a pseudo-tty allocation (which is what you get when you log in normally via ssh.)
answered Oct 3 '11 at 2:55
Ryan FoxRyan Fox
53654
didn't help, unfortunately. This also might be problem with MTU, but neither of it helped
– Nick Roz
Sep 9 '16 at 23:48
See Magnus' comment below ref using-tt- that worked for me when -t didn't.
– Tom Dalton
Mar 26 '18 at 13:35
add a comment |
Use ssh -t ... to force a pseudo-tty allocation (which is what you get when you log in normally via ssh.)
answered Oct 3 '11 at 2:55
Ryan FoxRyan Fox
53654
didn't help, unfortunately. This also might be problem with MTU, but neither of it helped
– Nick Roz
Sep 9 '16 at 23:48
See Magnus' comment below ref using-tt- that worked for me when -t didn't.
– Tom Dalton
Mar 26 '18 at 13:35
add a comment |
Use ssh -t ... to force a pseudo-tty allocation (which is what you get when you log in normally via ssh.)
answered Oct 3 '11 at 2:55
Ryan FoxRyan Fox
53654
Use ssh -t ... to force a pseudo-tty allocation (which is what you get when you log in normally via ssh.)
answered Oct 3 '11 at 2:55
Ryan FoxRyan Fox
53654
answered Oct 3 '11 at 2:55
Ryan FoxRyan Fox
53654
answered Oct 3 '11 at 2:55
Ryan FoxRyan Fox
53654
answered Oct 3 '11 at 2:55
Ryan FoxRyan Fox
53654
53654
didn't help, unfortunately. This also might be problem with MTU, but neither of it helped
– Nick Roz
Sep 9 '16 at 23:48
See Magnus' comment below ref using-tt- that worked for me when -t didn't.
– Tom Dalton
Mar 26 '18 at 13:35
add a comment |
didn't help, unfortunately. This also might be problem with MTU, but neither of it helped
– Nick Roz
Sep 9 '16 at 23:48
See Magnus' comment below ref using-tt- that worked for me when -t didn't.
– Tom Dalton
Mar 26 '18 at 13:35
didn't help, unfortunately. This also might be problem with MTU, but neither of it helped
– Nick Roz
Sep 9 '16 at 23:48
didn't help, unfortunately. This also might be problem with MTU, but neither of it helped
– Nick Roz
Sep 9 '16 at 23:48
See Magnus' comment below ref using
-tt - that worked for me when -t didn't.– Tom Dalton
Mar 26 '18 at 13:35
See Magnus' comment below ref using
-tt - that worked for me when -t didn't.– Tom Dalton
Mar 26 '18 at 13:35
add a comment |
To expand a little bit on Ryan Fox's answer:
Many programs (most? - it's the default for any C program) line-buffer stdout when they're talking to a terminal, but fully buffer it otherwise. (The C standard specifies that stdout is initially fully buffered when it "can be determined not to refer to an interactive device".)
So what you're seeing is that the output of the program you're running remotely (as given to stdout) isn't line-buffered; ssh is just passing through what it gets when it gets it. (I think ssh actually does no buffering at all on its output - that would be the least magical way to make sure that the user sees what the remote program intended.)
edited Oct 3 '11 at 10:59
David Wolever
1,30421214
answered Oct 3 '11 at 3:25
Dave VanderviesDave Vandervies
23112
An anonymous user suggests that stdout is fully buffered, not line buffered
– Michael Mrozek♦
Oct 3 '11 at 3:53
Dave Vandervies has told me out-of-band that he was the one who made the edit, and that it is correct (ie, stdout is initially fully buffered, not line buffered).
– David Wolever
Oct 3 '11 at 6:05
add a comment |
To expand a little bit on Ryan Fox's answer:
Many programs (most? - it's the default for any C program) line-buffer stdout when they're talking to a terminal, but fully buffer it otherwise. (The C standard specifies that stdout is initially fully buffered when it "can be determined not to refer to an interactive device".)
So what you're seeing is that the output of the program you're running remotely (as given to stdout) isn't line-buffered; ssh is just passing through what it gets when it gets it. (I think ssh actually does no buffering at all on its output - that would be the least magical way to make sure that the user sees what the remote program intended.)
edited Oct 3 '11 at 10:59
David Wolever
1,30421214
answered Oct 3 '11 at 3:25
Dave VanderviesDave Vandervies
23112
An anonymous user suggests that stdout is fully buffered, not line buffered
– Michael Mrozek♦
Oct 3 '11 at 3:53
Dave Vandervies has told me out-of-band that he was the one who made the edit, and that it is correct (ie, stdout is initially fully buffered, not line buffered).
– David Wolever
Oct 3 '11 at 6:05
add a comment |
To expand a little bit on Ryan Fox's answer:
Many programs (most? - it's the default for any C program) line-buffer stdout when they're talking to a terminal, but fully buffer it otherwise. (The C standard specifies that stdout is initially fully buffered when it "can be determined not to refer to an interactive device".)
So what you're seeing is that the output of the program you're running remotely (as given to stdout) isn't line-buffered; ssh is just passing through what it gets when it gets it. (I think ssh actually does no buffering at all on its output - that would be the least magical way to make sure that the user sees what the remote program intended.)
edited Oct 3 '11 at 10:59
David Wolever
1,30421214
answered Oct 3 '11 at 3:25
Dave VanderviesDave Vandervies
23112
To expand a little bit on Ryan Fox's answer:
Many programs (most? - it's the default for any C program) line-buffer stdout when they're talking to a terminal, but fully buffer it otherwise. (The C standard specifies that stdout is initially fully buffered when it "can be determined not to refer to an interactive device".)
So what you're seeing is that the output of the program you're running remotely (as given to stdout) isn't line-buffered; ssh is just passing through what it gets when it gets it. (I think ssh actually does no buffering at all on its output - that would be the least magical way to make sure that the user sees what the remote program intended.)
edited Oct 3 '11 at 10:59
David Wolever
1,30421214
answered Oct 3 '11 at 3:25
Dave VanderviesDave Vandervies
23112
edited Oct 3 '11 at 10:59
David Wolever
1,30421214
edited Oct 3 '11 at 10:59
David Wolever
1,30421214
edited Oct 3 '11 at 10:59
David Wolever
1,30421214
1,30421214
answered Oct 3 '11 at 3:25
Dave VanderviesDave Vandervies
23112
answered Oct 3 '11 at 3:25
Dave VanderviesDave Vandervies
23112
answered Oct 3 '11 at 3:25
Dave VanderviesDave Vandervies
23112
23112
An anonymous user suggests that stdout is fully buffered, not line buffered
– Michael Mrozek♦
Oct 3 '11 at 3:53
Dave Vandervies has told me out-of-band that he was the one who made the edit, and that it is correct (ie, stdout is initially fully buffered, not line buffered).
– David Wolever
Oct 3 '11 at 6:05
add a comment |
An anonymous user suggests that stdout is fully buffered, not line buffered
– Michael Mrozek♦
Oct 3 '11 at 3:53
Dave Vandervies has told me out-of-band that he was the one who made the edit, and that it is correct (ie, stdout is initially fully buffered, not line buffered).
– David Wolever
Oct 3 '11 at 6:05
An anonymous user suggests that stdout is fully buffered, not line buffered
– Michael Mrozek♦
Oct 3 '11 at 3:53
An anonymous user suggests that stdout is fully buffered, not line buffered
– Michael Mrozek♦
Oct 3 '11 at 3:53
Dave Vandervies has told me out-of-band that he was the one who made the edit, and that it is correct (ie, stdout is initially fully buffered, not line buffered).
– David Wolever
Oct 3 '11 at 6:05
Dave Vandervies has told me out-of-band that he was the one who made the edit, and that it is correct (ie, stdout is initially fully buffered, not line buffered).
– David Wolever
Oct 3 '11 at 6:05
add a comment |
To expand even more on Ryan Fox's answer, ssh -t didn't work for me either, but ssh -tt did. See the ssh man page about -t:
Multiple -t options force tty allocation, even if ssh has no local tty
edited 6 mins ago
PRY
2,55831026
answered Nov 23 '17 at 8:06
Magnus BergMagnus Berg
5111
add a comment |
To expand even more on Ryan Fox's answer, ssh -t didn't work for me either, but ssh -tt did. See the ssh man page about -t:
Multiple -t options force tty allocation, even if ssh has no local tty
edited 6 mins ago
PRY
2,55831026
answered Nov 23 '17 at 8:06
Magnus BergMagnus Berg
5111
add a comment |
To expand even more on Ryan Fox's answer, ssh -t didn't work for me either, but ssh -tt did. See the ssh man page about -t:
Multiple -t options force tty allocation, even if ssh has no local tty
edited 6 mins ago
PRY
2,55831026
answered Nov 23 '17 at 8:06
Magnus BergMagnus Berg
5111
To expand even more on Ryan Fox's answer, ssh -t didn't work for me either, but ssh -tt did. See the ssh man page about -t:
Multiple -t options force tty allocation, even if ssh has no local tty
edited 6 mins ago
PRY
2,55831026
answered Nov 23 '17 at 8:06
Magnus BergMagnus Berg
5111
edited 6 mins ago
PRY
2,55831026
edited 6 mins ago
PRY
2,55831026
edited 6 mins ago
PRY
2,55831026
2,55831026
answered Nov 23 '17 at 8:06
Magnus BergMagnus Berg
5111
answered Nov 23 '17 at 8:06
Magnus BergMagnus Berg
5111
answered Nov 23 '17 at 8:06
Magnus BergMagnus Berg
5111
5111
add a comment |
add a comment |
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