How to list cron jobs?

Question

PHP

Is there a way to list cron jobs using PHP?
The only solution that came to mind:

$text = shell_exec('crontab -l');
echo $text;

Does not help!
Who has any thoughts?

Answer 1

It's strange that it doesn't help you.

php > $text = shell_exec('crontab -l'); echo $text;
# Edit this file to introduce tasks to be run by cron.
# 
# Each task to run has to be defined through a single line
# indicating with different fields when the task will be run
# and what command to run for the task
# 
# To define the time you can provide concrete values for
# minute (m), hour (h), day of month (dom), month (mon),
# and day of week (dow) or use '*' in these fields (for 'any').# 
# Notice that tasks will be started based on the cron's system
# daemon's notion of time and timezones.
# 
# Output of the crontab jobs (including errors) is sent through
# email to the user the crontab file belongs to (unless redirected).
# 
# For example, you can run a backup of all your user accounts
# at 5 a.m every week with:
# 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/
# 
# For more information see the manual pages of crontab(5) and cron(8)
# 
# m h  dom mon dow   command

Answer 2

echo `sudo crontab -u $user -l`;
The user running the script must have sudo permissions for the crontab command, otherwise they will only be able to see their own listchroot -l

Answer 3

If you're trying to run a command such as "gunzip -t" in shell_exec and getting an empty result, you might need to add 2>&1 to the end of the command
Note:
This function can return NULL in two cases: if an error occurred or if the command being executed does not output anything. Do not use this function to determine if a command was successful. Use exec() instead, as it provides a way to check the return code.