# crontab
-bash: crontab: command not found

# yum -y install vixie-cron
Loaded plugins: fastestmirror, refresh-packagekit, security
Existing lock /var/run/yum.pid: another copy is running as pid 25960.
Another app is currently holding the yum lock; waiting for it to exit...

#rm -f /var/run/yum.pid

# yum -y install vixie-cron
Loaded plugins: fastestmirror, refresh-packagekit, security
Determining fastest mirrors
 * base: mirrors.btte.net
 * extras: mirrors.sina.cn
 * updates: mirrors.sina.cn
base                                         | 3.7 kB  00:00  
extras                                         | 3.4 kB  00:00  
extras/primary_db                                      | 32 kB  00:00  
updates                                         | 3.4 kB  00:00  
updates/primary_db                                      | 1.9 MB  00:07  
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package cronie.x86_64 0:1.4.4-15.el6 will be installed
--> Processing Dependency: dailyjobs for package: cronie-1.4.4-15.el6.x86_64
--> Processing Dependency: /usr/sbin/sendmail for package: cronie-1.4.4-15.el6.x86_64
--> Running transaction check
---> Package cronie-anacron.x86_64 0:1.4.4-15.el6 will be installed
--> Processing Dependency: crontabs for package: cronie-anacron-1.4.4-15.el6.x86_64
---> Package sendmail.x86_64 0:8.14.4-9.el6 will be installed
--> Processing Dependency: procmail for package: sendmail-8.14.4-9.el6.x86_64
--> Running transaction check
---> Package crontabs.noarch 0:1.10-33.el6 will be installed
---> Package procmail.x86_64 0:3.22-25.1.el6_5.1 will be installed
--> Finished Dependency Resolution
Dependencies Resolved
===============================================================================================================================================================================================
 Package           Arch          Version            Repository        Size
===============================================================================================================================================================================================
Installing:
 cronie           x86_64         1.4.4-15.el6           base         74 k
Installing for dependencies:
 cronie-anacron         x86_64         1.4.4-15.el6           base         31 k
 crontabs           noarch         1.10-33.el6           base         10 k
 procmail           x86_64         3.22-25.1.el6_5.1          base         162 k
 sendmail           x86_64         8.14.4-9.el6           base         716 k
Transaction Summary
===============================================================================================================================================================================================
Install  5 Package(s)
Total download size: 994 k
Installed size: 2.1 M
Downloading Packages:
(1/5): cronie-1.4.4-15.el6.x86_64.rpm                                 | 74 kB  00:00  
(2/5): cronie-anacron-1.4.4-15.el6.x86_64.rpm                               | 31 kB  00:00  
(3/5): crontabs-1.10-33.el6.noarch.rpm                                 | 10 kB  00:00  
(4/5): procmail-3.22-25.1.el6_5.1.x86_64.rpm                               | 162 kB  00:00  
(5/5): sendmail-8.14.4-9.el6.x86_64.rpm                                 | 716 kB  00:00  
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Total                                       1.3 MB/s | 994 kB  00:00  
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
 Installing : procmail-3.22-25.1.el6_5.1.x86_64                                   1/5 
 Installing : sendmail-8.14.4-9.el6.x86_64                                    2/5 
 Installing : cronie-1.4.4-15.el6.x86_64                                     3/5 
 Installing : crontabs-1.10-33.el6.noarch                                     4/5 
 Installing : cronie-anacron-1.4.4-15.el6.x86_64                                   5/5 
ERROR:dbus.proxies:Introspect error on :1.2513:/org/freedesktop/PackageKit: dbus.exceptions.DBusException: org.freedesktop.DBus.Error.NoReply: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken.
Unable to send message to PackageKit
 Verifying : crontabs-1.10-33.el6.noarch                                     1/5 
 Verifying : cronie-anacron-1.4.4-15.el6.x86_64                                   2/5 
 Verifying : sendmail-8.14.4-9.el6.x86_64                                    3/5 
 Verifying : cronie-1.4.4-15.el6.x86_64                                     4/5 
 Verifying : procmail-3.22-25.1.el6_5.1.x86_64                                   5/5 
Installed:
 cronie.x86_64 0:1.4.4
15.el6              
Dependency Installed:
 cronie-anacron.x86_64 0:1.4.4-15.el6    crontabs.noarch 0:1.10-33.el6    procmail.x86_64 0:3.22-25.1.el6_5.1    sendmail.x86_64 0:8.14.4-9.el6    
Complete!

# crontab -h
crontab：无效选项 -- h
crontab: usage error: unrecognized option
usage: crontab [-u user] file
 crontab [-u user] [ -e | -l | -r ]
  (default operation is replace, per 1003.2)
 -e (edit user's crontab)
 -l (list user's crontab)
 -r (delete user's crontab)
 -i (prompt before deleting user's crontab)
 -s (selinux context)

/sbin/service crond start //启动服务 
/sbin/service crond stop //关闭服务 
/sbin/service crond restart //重启服务 
/sbin/service crond reload //重新载入配置 
/sbin/service crond status //查看状态

# service crond start 
# service crond stop 
# service crond restart 
# service crond reload 
# service crond status

/sbin/service crond start