Cron job linux location

Linux / UNIX Crontab File Location

I login to my UNIX system as a normal user. However, I need to update my cronjob entry. But, I can’t find where the crontab file is. How do I find out my crontab file location?

By default cron searches its spool area /var/spool/cron/ directory for crontab files. All files which are named after username i.e. accounts in /etc/passwd file. So if your username is [donotprint]

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[/donotprint]vivek, crontab file location should be /var/spool/cron/$USER i.e. /var/spool/cron/vivek. Note that cron in this directory should not be accessed directly – the crontab command should be used to access and update them as follows:

To view your crontab file (cron jobs) type:
crontab -l

Directory for personal crontab files

Linux and Unix-like operating system may change the default from /var/spool/cron/ to something else. Use the following as a guideline for your OS (assuming that user name is vivek):

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1. Mac OS X – /usr/lib/cron/tabs/ (user cron location /usr/lib/cron/tabs/vivek )
2. FreeBSD/OpenBSD/NetBSD – /var/cron/tabs/ (user cron location /var/cron/tabs/vivek )
3. CentOS/Red Hat/RHEL/Fedora/Scientific Linux – /var/spool/cron/ (user cron location /var/spool/cron/vivek )
4. Debian / Ubuntu Linux – /var/spool/cron/crontabs/ (user cron location /var/spool/cron/crontabs/vivek )
5. HP-UX Unix – /var/spool/cron/crontabs/ (user cron location /var/spool/cron/crontabs/vivek )
6. IBM AIX Unix – /var/spool/cron/ (user cron location /var/spool/cron/vivek )

I suggest that you read local cron man page to get exact location for directory for personal crontab or use the above two commands.

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Location of the crontab file

as many (most?) others, I edit my crontab via crontab -e , where I keep all routine operations such as incremental backup, ntpdate, various rsync operations, as well as making my desktop background christmas themed once a year. From what I’ve understood, on a fresh install or new user, this also automatically creates the file if it doesn’t exist. However, I want to copy this file to another user, so where is the actual file that I’m editing?

If this varies between distros, I’m using Centos5 and Mint 17

2 Answers 2

The location of cron files for individual users is /var/spool/cron/crontabs/ .
From man crontab :

Each user can have their own crontab, and though these are files in /var/spool/cron/crontabs , they are not intended to be edited directly.

heemayl is correct about the location of crontab files on Linux, but it might be different on other operating systems and «theoretically» is could also be in a different location on Linux. Essentially, when a special interface is provided to access the files, you should use it. This will ensure that cron gets to check the files before installing them, makes sure the files have the permissions it needs them to have, etc.

Therefore you should copy a crontab from one user to another using that interface, like this, not by accessing the files directly.

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What is the ‘working directory’ when cron executes a job?

I have a script that works when I run it from the command line, but when I schedule it with cron I get errors that it cannot find files or commands. My question is twofold:

When I schedule a cron job using crontab -e , does it use my user ID as the basis for its permissions? Or does it use a cron user ID of some sort and its related permissions?

When a cron job is launched, what is the working directory? Is it the directory where I specify the script to run, or a different directory?

Here is my cron job:

Here is the actual script:

Here are the errors I get when I view the mail message produced by cron :

It cannot find the template.txt but it resides in the same directory as the script. It also cannot run ssmtp , but I can as my user. What am I missing to get this to work properly?

7 Answers 7

Add cd /home/xxxx/Documents/Scripts/ if you want your job to run in that directory. There’s no reason why cron would change to that particular directory. Cron runs your commands in your home directory.

As for ssmtp , it might not be in your default PATH . Cron’s default path is implementation-dependent, so check your man page, but in all likelihood ssmtp is in /usr/sbin which is not in your default PATH , only root’s.

If your cronjob is a bash script, the following will CD to the location of your script (assuming that you’re using absolute path in your cron definition):

To answer question 1: if you run crontab -e as your own user the jobs will be scheduled in that user’s crontab and will thus run with the permissions of that user.

But you need to consider that the jobs will run in a non-interactive shell meaning that the $PATH might be different from the one you have when running the script from the command line.

It is best to always use full paths in scripts, especially if you plan to schedule them via at/cron etc.

I would also recommend using full paths to all files to avoid exactly the problems you see.

To prevent race conditions and other security issues you should also use mktemp to make sure the file you read is not modified by anything outside your script.

So I’d change the script to something like:

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How to get CRON to call in the correct PATHs

I’m trying to get cron to call in the correct PATHs. When I run a Python script from shell the script runs fine as it uses the PATHs set in bashrc but when I use cron all the PATHs are not used from bashrc. Is there a file I can enter the PATHs into for cron like bashrc or a way to call the PATHs from bashrc?

Sorry I don’t think I worded this correctly, I can get the correct script to run (meaning the PATH to the script in crontab is not the problem here), it’s just when that script is running I run a build and this uses the PATHs set in .bashrc . When I run the script when I’m logged in, the .bashrc PATHs are pulled in. Since cron doesn’t run in a shell per say it does not pull in .bashrc . Is there a way of pulling this in without having to write a bash script wrapper?

/crontab_path.txt and checking the file after a minute.

15 Answers 15

I used /etc/crontab . I used vi and entered in the PATHs I needed into this file and ran it as root. The normal crontab overwrites PATHs that you have set up. A good tutorial on how to do this.

The systemwide cron file looks like this:

Most likely, cron is running in a very sparse environment. Check the environment variables cron is using by appending a dummy job which dumps env to a file like this:

Compare that with the output of env in a normal shell session.

You can prepend your own environment variables to the local crontab by defining them at the top of your crontab.

Here’s a quick fix to prepend $PATH to the current crontab:

The resulting crontab will look similar to chrissygormley’s answer, with PATH defined before the crontab rules.

You should put full paths in your crontab . That’s the safest option.
If you don’t want to do that you can put a wrapper script around your programs, and set the PATH in there.

Also anything called from cron should be be very careful about the programs it runs, and probably set its own choice for the PATH variable.

If you don’t know where the command is that you want execute which from your shell and it’ll tell you the path.

So once your program is running, the first thing it should do is set PATH and any other required variable (e.g. LD_LIBRARY_PATH ) to the values that are required for the script to run.
Basically instead of thinking how to modify the cron environment to make it more suitable for your program/script — make your script handle the environment it’s given, by setting an appropriate one when it starts.

Setting PATH right before the command line in my crontab worked for me:

Adding a PATH definition into the user crontab with correct values will help. I’ve filled mine with this line on top (after comments, and before cron jobs):

And it’s enough to get all my scripts working. Include any custom path there if you need to.

Make your variables work for you, this will allow access t

Define your PATH in /etc/profile.d/*.sh

Files with the .sh extension in the /etc/profile.d directory get executed whenever a bash login shell is entered (e.g. when logging in from the console or over ssh), as well as by the DisplayManager when the desktop session loads.

You can for instance create the file /etc/profile.d/myenvvars.sh and set variables like this:

Execute crontab with login option!

Problem

Your script works when you run it from the console but fails in cron.

Cause

Your crontab doesn’t have the right path variables (and possibly shell)

Solution

Add your current shell and path the crontab

Script to do it for you

Source

Sample Output

The default environment for cron jobs is very sparse and may be very different from the environment you develop your python scripts in. For a script that might be run in cron, any environment that you depend on should be set explicitly. In the cron file itself, include full paths to python executables and to your python scripts.

On my AIX cron picks up it’s environmental variables from /etc/environment ignoring what is set in the .profile.

Edit: I also checked out a couple of Linux boxes of various ages and these appear to have this file as well, so this is likely not AIX specific.

I checked this using joemaller’s cron suggestion and checking the output before and after editing the PATH variable in /etc/environment.

If you don’t want to have to make the same edits in various places, then roughly do this:

The . space and then the path to .bashrc and the && command are the magic there to get your environment changes into the running bash shell. Too, if you really want the shell to be bash, it is a good idea to have a line in your crontab:

Hope it helps someone!

Set the required PATH in your cron

Save and exit :wq

I know this has been answered already, but I thought that his would be useful to some. I had a similar issue that I recently solved (found here) and here are the highlights of the steps I took to answer this question:

make sure that you have the variables you need in PYTHONPATH (found here and here and for more info here) inside the .profile or .bash_profile for any shell you want to test your script in to make sure it works.

edit your crontab to include the directories needed to run your script in a cron job (found here and here)

a) be sure to include the root directory in the PATH variable (.) as explained here (basically if you are running an executable with your command it needs to be able to find root or the directory where the executable is stored) and probably these (/sbin:/bin:/usr/sbin:/usr/bin)

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How to List, Display, & View all Current Cron Jobs in Linux

Home » SysAdmin » How to List, Display, & View all Current Cron Jobs in Linux

Cron is a Linux utility for scheduling scripts and commands. This guide will show you several options to view current cron jobs scheduled in the crontab list.

• A user account with sudo privileges
• Access to a terminal window / command line (Ctrl+Alt+T, Ctrl+Alt+F2)

Listing Cron Jobs in Linux

How to List all Active Cron Jobs Running

To list all scheduled cron jobs for the current user, enter:

Cron jobs are typically located in the spool directories. They are stored in tables called crontabs. You can find them in /var/spool/cron/crontabs. The tables contain the cron jobs for all users, except the root user.

The root user can use the crontab for the whole system.

To display contents of the root user’s crontab, use the less command:

The system returns an output like the following:

The /etc/crontab file can be edited using a text editor like nano:

In RedHat-based systems, this file is located at /etc/cron.d.

The /etc/ directory has additional cron subdirectories to organize hourly, daily, weekly, and monthly tasks. The ls (list) command displays files and directories. Use the -la option to list all entries in long format.

View Cron Jobs by User

To list cron jobs that belong to a specific user, run the following command:

Replace [username] with the actual username you’re viewing.

How to List Hourly Cron Jobs

To list hourly cron jobs enter the following in the terminal window:

The output should appear similar to this:

How to List Daily Cron Jobs

To list daily cron jobs, enter the command:

The results will look similar to the following output:

How to Display Weekly Cron Jobs

To display weekly cron jobs:

The results will look something like the following:

How to List Monthly Cron Jobs

To display monthly cron jobs use the ls command in this format:

The results appear as:

View Software Specific Cron Jobs

To view software specefic cron tasks, start by viewing a list of cron tasks:

Use the cat command to display the contents of update-notifier-common :

The results will look similar to:

Now you know how to navigate through the cron jobs on your machine. Cron is a helpful utility for scheduling tasks such as running a job at reboot. Use the commands from this guide to sort and display tasks scheduled through the cron tool.

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