Cron runs only once instead every minute
9
I'm trying to run a script every minute (on a Docker container running Ubuntu 16.04)
The /etc/echo.sh simply echo the word "hi"
cat /etc/crontab
* * * * * root /etc/echo.sh > /var/log/cron.log 2>&1
/etc/init.d/cron reload
* Reloading configuration files for periodic command scheduler cron [ OK ]
tail -f /var/log/cron.log
hi
After printing "hi" once, nothing happens anymore.
Any ideas why?
cron docker ubuntu-16.04 crontab
asked 11 hours ago
SigSig
20628
add a comment |
9
I'm trying to run a script every minute (on a Docker container running Ubuntu 16.04)
The /etc/echo.sh simply echo the word "hi"
cat /etc/crontab
* * * * * root /etc/echo.sh > /var/log/cron.log 2>&1
/etc/init.d/cron reload
* Reloading configuration files for periodic command scheduler cron [ OK ]
tail -f /var/log/cron.log
hi
After printing "hi" once, nothing happens anymore.
Any ideas why?
cron docker ubuntu-16.04 crontab
asked 11 hours ago
SigSig
20628
add a comment |
9
9
9
1
I'm trying to run a script every minute (on a Docker container running Ubuntu 16.04)
The /etc/echo.sh simply echo the word "hi"
cat /etc/crontab
* * * * * root /etc/echo.sh > /var/log/cron.log 2>&1
/etc/init.d/cron reload
* Reloading configuration files for periodic command scheduler cron [ OK ]
tail -f /var/log/cron.log
hi
After printing "hi" once, nothing happens anymore.
Any ideas why?
cron docker ubuntu-16.04 crontab
asked 11 hours ago
SigSig
20628
I'm trying to run a script every minute (on a Docker container running Ubuntu 16.04)
The /etc/echo.sh simply echo the word "hi"
cat /etc/crontab
* * * * * root /etc/echo.sh > /var/log/cron.log 2>&1
/etc/init.d/cron reload
* Reloading configuration files for periodic command scheduler cron [ OK ]
tail -f /var/log/cron.log
hi
After printing "hi" once, nothing happens anymore.
Any ideas why?
cron docker ubuntu-16.04 crontab
cron docker ubuntu-16.04 crontab
asked 11 hours ago
SigSig
20628
asked 11 hours ago
SigSig
20628
asked 11 hours ago
SigSig
20628
asked 11 hours ago
SigSig
20628
asked 11 hours ago
SigSig
20628
20628
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
21
The script does run every minute but > truncates the file each time.
If the file does not exist, it shall be created; otherwise, it shall be truncated to be an empty file after being opened.
(source)
Use >> instead to append to the file.
answered 11 hours ago
Kamil MaciorowskiKamil Maciorowski
26.7k155681
Won'ttailsaytail: cron.log: file truncatedif the file is truncated? Or am I misunderstanding how tail works
– Ferrybig
7 hours ago
1
@Ferrybig Iftailnotices the short moment between truncating and placinghiback, then it will. In my Kubuntuecho hi > cron.logtriggers the message fromtailin about half the cases. It's a race condition so your (and the OP's) mileage may vary.
– Kamil Maciorowski
7 hours ago
1
And this is why you always usedateinstead ofecho hiwhen testing something like this.
– marcelm
2 hours ago
add a comment |
Your Answer
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "3"
};
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: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
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
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
var $window = $(window),
onScroll = function(e) {
var $elem = $('.new-login-left'),
docViewTop = $window.scrollTop(),
docViewBottom = docViewTop + $window.height(),
elemTop = $elem.offset().top,
elemBottom = elemTop + $elem.height();
if ((docViewTop elemBottom)) {
StackExchange.using('gps', function() { StackExchange.gps.track('embedded_signup_form.view', { location: 'question_page' }); });
$window.unbind('scroll', onScroll);
}
};
$window.on('scroll', onScroll);
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fsuperuser.com%2fquestions%2f1403597%2fcron-runs-only-once-instead-every-minute%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
21
The script does run every minute but > truncates the file each time.
If the file does not exist, it shall be created; otherwise, it shall be truncated to be an empty file after being opened.
(source)
Use >> instead to append to the file.
answered 11 hours ago
Kamil MaciorowskiKamil Maciorowski
26.7k155681
Won'ttailsaytail: cron.log: file truncatedif the file is truncated? Or am I misunderstanding how tail works
– Ferrybig
7 hours ago
1
@Ferrybig Iftailnotices the short moment between truncating and placinghiback, then it will. In my Kubuntuecho hi > cron.logtriggers the message fromtailin about half the cases. It's a race condition so your (and the OP's) mileage may vary.
– Kamil Maciorowski
7 hours ago
1
And this is why you always usedateinstead ofecho hiwhen testing something like this.
– marcelm
2 hours ago
add a comment |
21
The script does run every minute but > truncates the file each time.
If the file does not exist, it shall be created; otherwise, it shall be truncated to be an empty file after being opened.
(source)
Use >> instead to append to the file.
answered 11 hours ago
Kamil MaciorowskiKamil Maciorowski
26.7k155681
Won'ttailsaytail: cron.log: file truncatedif the file is truncated? Or am I misunderstanding how tail works
– Ferrybig
7 hours ago
1
@Ferrybig Iftailnotices the short moment between truncating and placinghiback, then it will. In my Kubuntuecho hi > cron.logtriggers the message fromtailin about half the cases. It's a race condition so your (and the OP's) mileage may vary.
– Kamil Maciorowski
7 hours ago
1
And this is why you always usedateinstead ofecho hiwhen testing something like this.
– marcelm
2 hours ago
add a comment |
21
21
21
The script does run every minute but > truncates the file each time.
If the file does not exist, it shall be created; otherwise, it shall be truncated to be an empty file after being opened.
(source)
Use >> instead to append to the file.
answered 11 hours ago
Kamil MaciorowskiKamil Maciorowski
26.7k155681
The script does run every minute but > truncates the file each time.
If the file does not exist, it shall be created; otherwise, it shall be truncated to be an empty file after being opened.
(source)
Use >> instead to append to the file.
answered 11 hours ago
Kamil MaciorowskiKamil Maciorowski
26.7k155681
edited 8 hours ago
answered 11 hours ago
Kamil MaciorowskiKamil Maciorowski
26.7k155681
answered 11 hours ago
Kamil MaciorowskiKamil Maciorowski
26.7k155681
answered 11 hours ago
Kamil MaciorowskiKamil Maciorowski
26.7k155681
26.7k155681
Won'ttailsaytail: cron.log: file truncatedif the file is truncated? Or am I misunderstanding how tail works
– Ferrybig
7 hours ago
1
@Ferrybig Iftailnotices the short moment between truncating and placinghiback, then it will. In my Kubuntuecho hi > cron.logtriggers the message fromtailin about half the cases. It's a race condition so your (and the OP's) mileage may vary.
– Kamil Maciorowski
7 hours ago
1
And this is why you always usedateinstead ofecho hiwhen testing something like this.
– marcelm
2 hours ago
add a comment |
Won'ttailsaytail: cron.log: file truncatedif the file is truncated? Or am I misunderstanding how tail works
– Ferrybig
7 hours ago
1
@Ferrybig Iftailnotices the short moment between truncating and placinghiback, then it will. In my Kubuntuecho hi > cron.logtriggers the message fromtailin about half the cases. It's a race condition so your (and the OP's) mileage may vary.
– Kamil Maciorowski
7 hours ago
1
And this is why you always usedateinstead ofecho hiwhen testing something like this.
– marcelm
2 hours ago
Won't
tail say tail: cron.log: file truncated if the file is truncated? Or am I misunderstanding how tail works– Ferrybig
7 hours ago
Won't
tail say tail: cron.log: file truncated if the file is truncated? Or am I misunderstanding how tail works– Ferrybig
7 hours ago
1
1
@Ferrybig If
tail notices the short moment between truncating and placing hi back, then it will. In my Kubuntu echo hi > cron.log triggers the message from tail in about half the cases. It's a race condition so your (and the OP's) mileage may vary.– Kamil Maciorowski
7 hours ago
@Ferrybig If
tail notices the short moment between truncating and placing hi back, then it will. In my Kubuntu echo hi > cron.log triggers the message from tail in about half the cases. It's a race condition so your (and the OP's) mileage may vary.– Kamil Maciorowski
7 hours ago
1
1
And this is why you always use
date instead of echo hi when testing something like this.– marcelm
2 hours ago
And this is why you always use
date instead of echo hi when testing something like this.– marcelm
2 hours ago
add a comment |
draft saved
draft discarded
Thanks for contributing an answer to Super User!
- 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
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
var $window = $(window),
onScroll = function(e) {
var $elem = $('.new-login-left'),
docViewTop = $window.scrollTop(),
docViewBottom = docViewTop + $window.height(),
elemTop = $elem.offset().top,
elemBottom = elemTop + $elem.height();
if ((docViewTop elemBottom)) {
StackExchange.using('gps', function() { StackExchange.gps.track('embedded_signup_form.view', { location: 'question_page' }); });
$window.unbind('scroll', onScroll);
}
};
$window.on('scroll', onScroll);
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fsuperuser.com%2fquestions%2f1403597%2fcron-runs-only-once-instead-every-minute%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
var $window = $(window),
onScroll = function(e) {
var $elem = $('.new-login-left'),
docViewTop = $window.scrollTop(),
docViewBottom = docViewTop + $window.height(),
elemTop = $elem.offset().top,
elemBottom = elemTop + $elem.height();
if ((docViewTop elemBottom)) {
StackExchange.using('gps', function() { StackExchange.gps.track('embedded_signup_form.view', { location: 'question_page' }); });
$window.unbind('scroll', onScroll);
}
};
$window.on('scroll', onScroll);
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
var $window = $(window),
onScroll = function(e) {
var $elem = $('.new-login-left'),
docViewTop = $window.scrollTop(),
docViewBottom = docViewTop + $window.height(),
elemTop = $elem.offset().top,
elemBottom = elemTop + $elem.height();
if ((docViewTop elemBottom)) {
StackExchange.using('gps', function() { StackExchange.gps.track('embedded_signup_form.view', { location: 'question_page' }); });
$window.unbind('scroll', onScroll);
}
};
$window.on('scroll', onScroll);
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
var $window = $(window),
onScroll = function(e) {
var $elem = $('.new-login-left'),
docViewTop = $window.scrollTop(),
docViewBottom = docViewTop + $window.height(),
elemTop = $elem.offset().top,
elemBottom = elemTop + $elem.height();
if ((docViewTop elemBottom)) {
StackExchange.using('gps', function() { StackExchange.gps.track('embedded_signup_form.view', { location: 'question_page' }); });
$window.unbind('scroll', onScroll);
}
};
$window.on('scroll', onScroll);
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
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
