Coreutils timeout(1) plays badly with man/less
I want to set a timeout to the less(1) command on our company's production server. Everyday we produce large log files on it, and despite the nightly batch job to archive/remove them, we sometimes get alerted on high disk usage because a (long-)running process can prevent a file from getting unlink(2)-ed physically due to the reference-counting semantics of POSIX filesystems.
To avoid the most common cases of such annoyances, I wrote a wrapper of less which runs it under timeout(1) so that idle less processes get automatically killed after several hours without keeping open files in the filesystem.
But it turned out to play badly with man(1): when the wrapper is launched by the man command via the PAGER environment variable, it stopped responding to any keyboard inputs. Here is a minimal reproducible test case:
$ PAGER='timeout 12h /bin/less' man man
After running this, ps fx output looks like this:
19415 pts/1 SNs 0:00 _ -bash
19854 pts/1 SN+ 0:00 _ man man
19867 pts/1 SN 0:00 _ timeout 12h /bin/less
19869 pts/1 TN 0:00 _ /bin/less
and I could only kill -KILL 19869 to regain an access to the terminal.
What did I get wrong here?
Why is the less process in the T state, as opposed to S?
terminal process-management timeout
asked 26 mins ago
nodakai
21719
add a comment |
I want to set a timeout to the less(1) command on our company's production server. Everyday we produce large log files on it, and despite the nightly batch job to archive/remove them, we sometimes get alerted on high disk usage because a (long-)running process can prevent a file from getting unlink(2)-ed physically due to the reference-counting semantics of POSIX filesystems.
To avoid the most common cases of such annoyances, I wrote a wrapper of less which runs it under timeout(1) so that idle less processes get automatically killed after several hours without keeping open files in the filesystem.
But it turned out to play badly with man(1): when the wrapper is launched by the man command via the PAGER environment variable, it stopped responding to any keyboard inputs. Here is a minimal reproducible test case:
$ PAGER='timeout 12h /bin/less' man man
After running this, ps fx output looks like this:
19415 pts/1 SNs 0:00 _ -bash
19854 pts/1 SN+ 0:00 _ man man
19867 pts/1 SN 0:00 _ timeout 12h /bin/less
19869 pts/1 TN 0:00 _ /bin/less
and I could only kill -KILL 19869 to regain an access to the terminal.
What did I get wrong here?
Why is the less process in the T state, as opposed to S?
terminal process-management timeout
asked 26 mins ago
nodakai
21719
Show us the wrapper please
– Rui F Ribeiro
20 mins ago
The only way I can reproduce this is if I temporarily putman/lessin the background throughCtrl+Z. Did you do that to run yourpscommand? That would putlessin a T state... UsingtimeoutinPAGERseems to work as expected on my OpenBSD system.
– Kusalananda
17 mins ago
add a comment |
I want to set a timeout to the less(1) command on our company's production server. Everyday we produce large log files on it, and despite the nightly batch job to archive/remove them, we sometimes get alerted on high disk usage because a (long-)running process can prevent a file from getting unlink(2)-ed physically due to the reference-counting semantics of POSIX filesystems.
To avoid the most common cases of such annoyances, I wrote a wrapper of less which runs it under timeout(1) so that idle less processes get automatically killed after several hours without keeping open files in the filesystem.
But it turned out to play badly with man(1): when the wrapper is launched by the man command via the PAGER environment variable, it stopped responding to any keyboard inputs. Here is a minimal reproducible test case:
$ PAGER='timeout 12h /bin/less' man man
After running this, ps fx output looks like this:
19415 pts/1 SNs 0:00 _ -bash
19854 pts/1 SN+ 0:00 _ man man
19867 pts/1 SN 0:00 _ timeout 12h /bin/less
19869 pts/1 TN 0:00 _ /bin/less
and I could only kill -KILL 19869 to regain an access to the terminal.
What did I get wrong here?
Why is the less process in the T state, as opposed to S?
terminal process-management timeout
asked 26 mins ago
nodakai
21719
I want to set a timeout to the less(1) command on our company's production server. Everyday we produce large log files on it, and despite the nightly batch job to archive/remove them, we sometimes get alerted on high disk usage because a (long-)running process can prevent a file from getting unlink(2)-ed physically due to the reference-counting semantics of POSIX filesystems.
To avoid the most common cases of such annoyances, I wrote a wrapper of less which runs it under timeout(1) so that idle less processes get automatically killed after several hours without keeping open files in the filesystem.
But it turned out to play badly with man(1): when the wrapper is launched by the man command via the PAGER environment variable, it stopped responding to any keyboard inputs. Here is a minimal reproducible test case:
$ PAGER='timeout 12h /bin/less' man man
After running this, ps fx output looks like this:
19415 pts/1 SNs 0:00 _ -bash
19854 pts/1 SN+ 0:00 _ man man
19867 pts/1 SN 0:00 _ timeout 12h /bin/less
19869 pts/1 TN 0:00 _ /bin/less
and I could only kill -KILL 19869 to regain an access to the terminal.
What did I get wrong here?
Why is the less process in the T state, as opposed to S?
terminal process-management timeout
terminal process-management timeout
asked 26 mins ago
nodakai
21719
asked 26 mins ago
nodakai
21719
asked 26 mins ago
nodakai
21719
asked 26 mins ago
nodakai
21719
asked 26 mins ago
nodakai
21719
21719
Show us the wrapper please
– Rui F Ribeiro
20 mins ago
The only way I can reproduce this is if I temporarily putman/lessin the background throughCtrl+Z. Did you do that to run yourpscommand? That would putlessin a T state... UsingtimeoutinPAGERseems to work as expected on my OpenBSD system.
– Kusalananda
17 mins ago
add a comment |
Show us the wrapper please
– Rui F Ribeiro
20 mins ago
The only way I can reproduce this is if I temporarily putman/lessin the background throughCtrl+Z. Did you do that to run yourpscommand? That would putlessin a T state... UsingtimeoutinPAGERseems to work as expected on my OpenBSD system.
– Kusalananda
17 mins ago
Show us the wrapper please
– Rui F Ribeiro
20 mins ago
Show us the wrapper please
– Rui F Ribeiro
20 mins ago
The only way I can reproduce this is if I temporarily put
man/less in the background through Ctrl+Z. Did you do that to run your ps command? That would put less in a T state... Using timeout in PAGER seems to work as expected on my OpenBSD system.– Kusalananda
17 mins ago
The only way I can reproduce this is if I temporarily put
man/less in the background through Ctrl+Z. Did you do that to run your ps command? That would put less in a T state... Using timeout in PAGER seems to work as expected on my OpenBSD system.– Kusalananda
17 mins ago
add a comment |
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Show us the wrapper please
– Rui F Ribeiro
20 mins ago
The only way I can reproduce this is if I temporarily put
man/lessin the background throughCtrl+Z. Did you do that to run yourpscommand? That would putlessin a T state... UsingtimeoutinPAGERseems to work as expected on my OpenBSD system.– Kusalananda
17 mins ago