Ubuntu: Use crontab to execute a job periodically

Create t1.sh in /home/vandy/crontab directory

#!/bin/sh
echo "=============`date`=================" >> /home/vandy/test1.log
env >> /home/vandy/test1.log

We can see the outputs in test1.log file

Create cronfile1 in /home/vandy/crontab directory

*/1 * * * * sh /home/vandy/crontab/t1.sh

t1.sh will be executed every 1 minute

Create run.sh in /home/vandy/crontab directory

#!/bin/sh
crontab cronfile1

Use crontab to call the job which is defined in cronfile1

Use commands to run

cd /home/vandy/crontab
sh run.sh

Running flow: run.sh –> cronfile1 –> t1.sh

Then the job will be started, and we can see the outputs in test1.log file

=============Sat Dec 14 14:15:01 CST 2013=================
HOME=/home/vandy
JRE_HOME=/usr/java/jdk1.6.0_26_x64/jre
LOGNAME=vandy
PATH=/usr/bin:/bin
SHELL=/bin/sh
CLASSPATH=$CLASSPATH:$JAVA_HOME/lib:$JAVA_HOME/jre/lib
JAVA_HOME=/usr/java/jdk1.6.0_26_x64
PWD=/home/vandy
=============Sat Dec 14 14:16:01 CST 2013=================
HOME=/home/vandy
JRE_HOME=/usr/java/jdk1.6.0_26_x64/jre
LOGNAME=vandy
PATH=/usr/bin:/bin
SHELL=/bin/sh
CLASSPATH=$CLASSPATH:$JAVA_HOME/lib:$JAVA_HOME/jre/lib
JAVA_HOME=/usr/java/jdk1.6.0_26_x64
PWD=/home/vandy
=============Sat Dec 14 14:17:01 CST 2013=================
HOME=/home/vandy
JRE_HOME=/usr/java/jdk1.6.0_26_x64/jre
LOGNAME=vandy
PATH=/usr/bin:/bin
SHELL=/bin/sh
CLASSPATH=$CLASSPATH:$JAVA_HOME/lib:$JAVA_HOME/jre/lib
JAVA_HOME=/usr/java/jdk1.6.0_26_x64
PWD=/home/vandy
=============Sat Dec 14 14:18:01 CST 2013=================
HOME=/home/vandy
JRE_HOME=/usr/java/jdk1.6.0_26_x64/jre
LOGNAME=vandy
PATH=/usr/bin:/bin
SHELL=/bin/sh
CLASSPATH=$CLASSPATH:$JAVA_HOME/lib:$JAVA_HOME/jre/lib
JAVA_HOME=/usr/java/jdk1.6.0_26_x64
PWD=/home/vandy

Use commands to see vandy’s jobs

vandy@vandy:~/crontab$ crontab -l
*/1 * * * * sh /home/vandy/crontab/t1.sh

Use commands to stop vandy’s jobs

vandy@vandy:~/crontab$ crontab -r
vandy@vandy:~/crontab$ crontab -l
no crontab for vandy

Reference

More about crontab