Pentru ca linux s\u0103 efectueze automat sarcini pe care altfel ar trebui s\u0103 le efectua\u021bi manual, cum ar fi rularea scripturilor \u0219i executarea comenzilor specifice, folosim un instrument numit cron. Pe sistemele Linux, utilitatea cron este modalitatea preferat\u0103 de a automatiza rularea scripturilor la intervale de timp specifice.<\/p>\n\n\n\n
\u00cen acest articol, vom aborda modul de vizualizare \/ listare a lucr\u0103rilor programate \u00een lista crontab.<\/p>\n\n\n\n
Cu cele mai multe aplica\u021bii Cron (de exemplu, Vixie-Cron – Debian \/ Ubuntu implicit, Cronie – Fedora implicit, Solaris Cron \u2026) ve\u021bi ob\u021bine lista de lucr\u0103ri cron programate pentru utilizatorul curent prin intermediul comenzii:<\/p>\n\n\n\n
$ crontab -l<\/p>\n\n\n\n
sau pentru un alt utilizator prin rularea comenzii:<\/p>\n\n\n\n
$ crontab -u username -l<\/p>\n\n\n\n
\u00cen mod alternativ, pute\u021bi verifica fi\u0219ierele spool. De obicei, acestea sunt salvate \u00een \/var\/spool\/cron, de ex. pentru vcron, urm\u0103torul director \/var\/spool\/cron\/crontabs con\u021bine toate crontab-urile configurate ale tuturor utilizatorilor – cu excep\u021bia utilizatorului root, care este, de asemenea, capabil s\u0103 configureze joburi prin intermediul crontab-ului din \u00eentregul sistem, care se afl\u0103 \u00een directorul \/etc\/crontab.<\/p>\n\n\n\n
Pentru a vedea aceste cron-uri v\u0103 pute\u021bi folosi de comanda „less” astfel:<\/p>\n\n\n\n
less \/etc\/crontab<\/p>\n\n\n\n
Exemplu de structur\u0103 crontab: <\/p>\n\n\n\n
SHELL=\/bin\/bash
\nPATH=\/sbin:\/bin:\/usr\/sbin:\/usr\/bin
\nMAILTO=root<\/p>\n\n\n\n
For details see man 4 crontabs<\/p>\n\n\n\n
Example of job definition:<\/p>\n\n\n\n
.–––––- minute (0 – 59)<\/p>\n\n\n\n
| .––––- hour (0 – 23)<\/p>\n\n\n\n
| | .–––- day of month (1 – 31)<\/p>\n\n\n\n
| | | .––- month (1 – 12) OR jan,feb,mar,apr \u2026<\/p>\n\n\n\n
| | | | .–- day of week (0 – 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat<\/p>\n\n\n\n
| | | | |<\/p>\n\n\n\n
* * * * * user-name command to be executed<\/p>\n\n\n\n
Pe computerul meu arat\u0103 a\u0219a:<\/p>\n\n\n\n
\/etc\/crontab: system-wide crontab<\/p>\n\n\n\n
Unlike any other crontab you don’t have to run the `crontab’<\/p>\n\n\n\n
command to install the new version when you edit this file<\/p>\n\n\n\n
and files \u00een \/etc\/cron.d. These files also have username fields,<\/p>\n\n\n\n
that none of the other crontabs do.<\/p>\n\n\n\n
SHELL=\/bin\/sh
\nPATH=\/usr\/local\/sbin:\/usr\/local\/bin:\/sbin:\/bin:\/usr\/sbin:\/usr\/bin<\/p>\n\n\n\n
m h dom mon dow user command<\/p>\n\n\n\n
17 * * * * root cd \/ && run-parts –report \/etc\/cron.hourly
\n25 6 * * * root test -x \/usr\/sbin\/anacron || ( cd \/ && run-parts –report \/etc\/cron.daily )
\n47 6 * * 7 root test -x \/usr\/sbin\/anacron || ( cd \/ && run-parts –report \/etc\/cron.weekly )
\n52 6 1 * * root test -x \/usr\/sbin\/anacron || ( cd \/ && run-parts –report \/etc\/cron.monthly )<\/p>\n\n\n\n
Cu cronie (utilitarul implicit de pe Fedora \/ CentOS), exist\u0103 un director de configurare \u00een stil cron.d pentru lucr\u0103rile cron de sistem, de asemenea:<\/p>\n\n\n\n
\/etc\/cron.d<\/p>\n\n\n\n
Ca \u00eentotdeauna, directorul cron.d simplific\u0103 men\u021binerea intr\u0103rilor de configurare care fac parte din diferite pachete.<\/p>\n\n\n\n
Pentru comoditate, majoritatea distribu\u021biilor ofer\u0103 \u0219i un director \u00een care scripturile link \/ stocate sunt executate periodic, de ex .:<\/p>\n\n\n\n
\/etc\/cron.daily
\n\/etc\/cron.hourly
\n\/etc\/cron.monthly
\n\/etc\/cron.weekly<\/p>\n\n\n\n
Cum s\u0103 afi\u0219a\u021bi joburile Cron pe or\u0103<\/p>\n\n\n\n
Pentru a enumera cronjob-urile setate la or\u0103, executa\u021bi comanda de mai jos:<\/p>\n\n\n\n
$ ls -la \/etc\/cron.hourly\/
\ntotal 12
\ndrwxr-xr-x 2 root root 4096 Apr 24 20:44 .
\ndrwxr-xr-x 96 root root 4096 May 19 17:12 ..
\n-rw-r–r– 1 root root 102 Feb 9 2013 .placeholder<\/p>\n\n\n\n
Cum s\u0103 afi\u0219a\u021bi joburile Cron pe zi<\/p>\n\n\n\n
Pentru a enumera cronjob-urile setate la zi, executa\u021bi comanda de mai jos:<\/p>\n\n\n\n
$ ls -la \/etc\/cron.daily\/
\ntotal 72
\ndrwxr-xr-x 2 root root 4096 Apr 24 20:46 .
\ndrwxr-xr-x 96 root root 4096 May 19 17:12 ..
\n-rw-r–r– 1 root root 102 Feb 9 2013 .placeholder
\n-rwxr-xr-x 1 root root 376 Apr 4 2014 apport
\n-rwxr-xr-x 1 root root 15481 Apr 10 2014 apt
\n-rwxr-xr-x 1 root root 314 Feb 18 2014 aptitude
\n-rwxr-xr-x 1 root root 355 Jun 4 2013 bsdmainutils
\n-rwxr-xr-x 1 root root 256 Mar 7 2014 dpkg
\n-rwxr-xr-x 1 root root 372 Jan 22 2014 logrotate
\n-rwxr-xr-x 1 root root 1261 Sep 23 2014 man-db
\n-rwxr-xr-x 1 root root 435 Jun 20 2013 mlocate
\n-rwxr-xr-x 1 root root 249 Feb 17 2014 passwd
\n-rwxr-xr-x 1 root root 2417 May 13 2013 popularity-contest
\n-rwxr-xr-x 1 root root 214 Mar 27 2017 update-notifier-common
\n-rwxr-xr-x 1 root root 328 Jul 18 2014 upstart<\/p>\n\n\n\n
Cum s\u0103 afi\u0219a\u021bi joburile Cron pe s\u0103pt\u0103m\u00e2n\u0103<\/p>\n\n\n\n
Pentru a enumera cronjob-urile setate la s\u0103pt\u0103m\u00e2n\u0103, executa\u021bi comanda de mai jos:<\/p>\n\n\n\n
$ ls -la \/etc\/cron.weekly\/
\ntotal 28
\ndrwxr-xr-x 2 root root 4096 Apr 24 20:46 .
\ndrwxr-xr-x 96 root root 4096 May 19 17:12 ..
\n-rw-r–r– 1 root root 102 Feb 9 2013 .placeholder
\n-rwxr-xr-x 1 root root 730 Feb 23 2014 apt-xapian-index
\n-rwxr-xr-x 1 root root 427 Apr 16 2014 fstrim
\n-rwxr-xr-x 1 root root 771 Sep 23 2014 man-db
\n-rwxr-xr-x 1 root root 211 Mar 27 2017 update-notifier-common<\/p>\n\n\n\n
Cum s\u0103 afi\u0219a\u021bi joburile Cron pe lun\u0103<\/p>\n\n\n\n
Pentru a enumera cronjob-urile setate la lun\u0103, executa\u021bi comanda de mai jos:<\/p>\n\n\n\n
$ ls -la \/etc\/cron.monthly\/
\ntotal 12
\ndrwxr-xr-x 2 root root 4096 Apr 24 20:44 .
\ndrwxr-xr-x 96 root root 4096 May 19 17:12 ..
\n-rw-r–r– 1 root root 102 Feb 9 2013 .placeholder<\/p>\n\n\n\n
Vizualiza\u021bi joburile Cron specifice unui anumit software<\/p>\n\n\n\n
Putem arunca o privire la un anumit cronjob prin rularea comenzii cat:<\/p>\n\n\n\n
$ cd \/etc\/cron.daily\/
\n$ ls -l
\ntotal 60
\n-rwxr-xr-x 1 root root 376 Apr 4 2014 apport
\n-rwxr-xr-x 1 root root 15481 Apr 10 2014 apt
\n-rwxr-xr-x 1 root root 314 Feb 18 2014 aptitude
\n-rwxr-xr-x 1 root root 355 Jun 4 2013 bsdmainutils
\n-rwxr-xr-x 1 root root 256 Mar 7 2014 dpkg
\n-rwxr-xr-x 1 root root 372 Jan 22 2014 logrotate
\n-rwxr-xr-x 1 root root 1261 Sep 23 2014 man-db
\n-rwxr-xr-x 1 root root 435 Jun 20 2013 mlocate
\n-rwxr-xr-x 1 root root 249 Feb 17 2014 passwd
\n-rwxr-xr-x 1 root root 2417 May 13 2013 popularity-contest
\n-rwxr-xr-x 1 root root 214 Mar 27 2017 update-notifier-common
\n-rwxr-xr-x 1 root root 328 Jul 18 2014 upstart<\/p>\n\n\n\n
$ cat update-notifier-common <\/p>\n\n\n\n
!\/bin\/sh<\/p>\n\n\n\n
set -e<\/p>\n\n\n\n
[ -x \/usr\/lib\/update-notifier\/package-data-downloader ] || exit 0<\/p>\n\n\n\n
Try to rerun any package data downloads that failed at package install time.<\/p>\n\n\n\n
\/usr\/lib\/update-notifier\/package-data-downloader<\/p>\n","protected":false},"excerpt":{"rendered":"
Pentru ca linux s\u0103 efectueze automat sarcini pe care altfel ar trebui s\u0103 le efectua\u021bi manual, cum ar fi rularea scripturilor \u0219i executarea comenzilor specifice, folosim un instrument numit cron. Pe sistemele Linux, utilitatea cron este modalitatea preferat\u0103 de a automatiza rularea scripturilor la intervale de timp specifice. \u00cen acest articol, vom aborda modul de<\/p>\n","protected":false},"author":1,"featured_media":1702,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[176,7],"class_list":["post-1700","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-how-to","tag-linux","tag-vps"],"yoast_head":"\n