crontab variables

1. Can I use variables in crontab?
2. How do you set a variable in crontab?
3. What environment variables does Cron use?
4. Does crontab use Bash_profile?
5. Where is crontab stored?
6. How do I use crontab?
7. What does crontab command do?
8. How do I run a crontab script?
9. What is ETC crontab file?
10. How do I export a crontab variable?
11. How do I see crontab logs?
12. What Shell does Cron use?

Can I use variables in crontab?

4 Answers. Yes, you can define and use variables in this way.

How do you set a variable in crontab?

Crontab Variables

The default path is set to PATH=/usr/bin:/bin . If the command you are executing is not present in the cron specified path, you can either use the absolute path to the command or change the cron $PATH variable. You can't implicitly append :$PATH as you would do with a regular script.

What environment variables does Cron use?

The default environment for a cron job consists of /etc/environment, and the default shell environment variables such as $PATH, $HOME and $PWD. Information in login files (for example, /etc/profile, ~/. profile and ~/.

Does crontab use Bash_profile?

By design, the settings in ~/. bash_profile , ~/. ... are for users to set things when bash plays the role of a shell (login shell, interractive shell). Think about environment you have in a xterm (interactive shell) or in ssh sessions (login shell) or in consoles (login shell).

Where is crontab stored?

The crontab files are stored in /var/spool/cron/crontabs . Several crontab files besides root are provided during SunOS software installation (see the following table). Besides the default crontab file, users can create crontab files to schedule their own system events.

How do I use crontab?

Opening Crontab

First, open a terminal window from your Linux desktop's applications menu. You can click the Dash icon, type Terminal and press Enter to open one if you're using Ubuntu. Use the crontab -e command to open your user account's crontab file. Commands in this file run with your user account's permissions.

What does crontab command do?

The crontab (abbreviation for “cron table”) is list of commands to execute the scheduled tasks at specific time. It allows the user to add, remove or modify the scheduled tasks.

How do I run a crontab script?

Automate running a script using crontab

1. Step 1: Go to your crontab file. Go to Terminal / your command line interface. ...
2. Step 2: Write your cron command. A Cron command first specifies (1) the interval at which you want to run the script followed by (2) the command to execute. ...
3. Step 3: Check that the cron command is working. ...
4. Step 4: Debugging potential problems.

What is ETC crontab file?

The /etc/crontab file is a special case file used to implement a system-wide crontab. /var/spool/cron/crontabs/$USER (or whatever the path happens to be) is an implementation detail. If you can schedule jobs using the crontab command, you should do so.

How do I export a crontab variable?

1. create a file with all the needed env var : #!/bin/bash. env | grep VAR1= > /etc/environment. ...
2. then build the crontab content, by calling the env file before calling the script that needs it, therefore start the cron service. (crontab -l ; echo '* * * * * . /

How do I see crontab logs?

Cron has an own reserved syslog facility, so you should have a look into /etc/syslog. conf (or the equivalent file in your distro) to see where messages of facility cron are sent. Popular destinations include /var/log/cron , /var/log/messages and /var/log/syslog .

What Shell does Cron use?

Cron Uses /bin/sh By Default, Not Bash

Bash ( /bin/bash ) is a common shell on most distros, and is an implementation of sh.