Coreutils timeout(1) plays badly with man/less












0














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?










share|improve this question






















  • 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


















0














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?










share|improve this question






















  • 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
















0












0








0


1





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?










share|improve this question













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






share|improve this question













share|improve this question











share|improve this question




share|improve this question










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 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




















  • 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


















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












0






active

oldest

votes











Your Answer








StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "106"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});


}
});














draft saved

draft discarded


















StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2funix.stackexchange.com%2fquestions%2f492941%2fcoreutils-timeout1-plays-badly-with-man-less%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown

























0






active

oldest

votes








0






active

oldest

votes









active

oldest

votes






active

oldest

votes
















draft saved

draft discarded




















































Thanks for contributing an answer to Unix & Linux Stack Exchange!


  • Please be sure to answer the question. Provide details and share your research!

But avoid



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


To learn more, see our tips on writing great answers.





Some of your past answers have not been well-received, and you're in danger of being blocked from answering.


Please pay close attention to the following guidance:


  • Please be sure to answer the question. Provide details and share your research!

But avoid



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


To learn more, see our tips on writing great answers.




draft saved


draft discarded














StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2funix.stackexchange.com%2fquestions%2f492941%2fcoreutils-timeout1-plays-badly-with-man-less%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown





















































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown

































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown







Popular posts from this blog

Accessing regular linux commands in Huawei's Dopra Linux

Can't connect RFCOMM socket: Host is down

Kernel panic - not syncing: Fatal Exception in Interrupt