How to run a cronjob every X minutes

Question

I m running a PHP script in a cronjob and I want to send emails every 5 minutes  My current  crontab  cronjob   10          usr bin php  mydomain in cromail php  gt   dev null 2 gt  amp 1   The cronmail php is as follows    lt  php  from    D      sender  subject    S    message    M    message   wordwrap  message  70   mail  myemail gmail com    subject   message   From   from n      gt    But I ve not received an email in 30 minutes with this configuration

User · Answer

---------------- minute  0 - 59        ------------- hour  0 - 23           ---------- day of month  1 - 31              ------- month  1 - 12  OR jan feb mar apr                    ---- day of week  0 - 6   Sunday 0 or 7  OR sun mon tue wed thu fri sat                                 user-name  command to be executed   To set for x minutes we need to set x minutes in the 1st argument and then the path of your script  For 15 mins    15           usr bin php  mydomain in cromail php  gt   dev null 2 gt  amp 1

User · Answer

You are setting your cron to run on 10th minute in every hour  To set it to every 5 mins change to   5          usr bin php  mydomain in cronmail php  gt   dev null 2 gt  amp 1

User · Answer

2 steps to check if a cronjob is working      Login on the server with the user that execute the cronjob Manually run php command      usr bin php  mydomain in cromail php   And check if any error is displayed

User · Answer

Your CRON should look like this     5          CronWTF is really usefull when you need to test out your CRON settings   Might be a good idea to pipe the output into a log file so you can see if your script is throwing any errors too - since you wont see them in your terminal   Also try using a shebang at the top of your PHP file  so the system knows where to find PHP  Such as      usr bin php  that way you can call the whole thing like this    5         php  path to script php  gt   path to logfile log

User · Answer

In a crontab file  the fields are    minute of the hour  hour of the day  day of the month  month of the year  day of the week    So   10         blah   means execute blah at 10 minutes past every hour   If you want every five minutes  use either     5         blah   meaning every minute but only every fifth one  or   0 5 10 15 20 25 30 35 40 45 50 55         blah   for older cron executables that don t understand the   x notation   If it still seems to be not working after that  change the command to something like   date  gt  gt  tmp debug cron pax txt   and monitor that file to ensure something s being written every five minutes  If so  there s something wrong with your PHP scripts  If not  there s something wrong with your cron daemon

User · Answer

If you want to run a cron every n minutes  there are a few possible options depending on the value of n   n divides 60  1  2  3  4  5  6  10  12  15  20  30   Here  the solution is straightforward by making use of the   notation     Example of job definition     ---------------- minute  0 - 59        ------------- hour  0 - 23           ---------- day of month  1 - 31              ------- month  1 - 12  OR jan feb mar apr                    ---- day of week  0 - 6   Sunday 0 or 7                                    command to be executed m-59 n               command   In the above  n represents the value n and m represents a value smaller than n or    This will execute the command at the minutes m m n m 2n      n does NOT divide 60  If n does not divide 60  you cannot do this cleanly with cron but it is possible  To do this you need to put a test in the cron where the test checks the time  This is best done when looking at the UNIX timestamp  the total seconds since 1970-01-01 00 00 00 UTC  Let s say we want to start to run the command the first time when Marty McFly arrived in Riverdale and then repeat it every n minutes later     date -d  2015-10-21 07 28 00    s  1445412480   For a cronjob to run every 42nd minute after  2015-10-21 07 28 00   the crontab would look like this     Example of job definition     ---------------- minute  0 - 59        ------------- hour  0 - 23           ---------- day of month  1 - 31              ------- month  1 - 12  OR jan feb mar apr                    ---- day of week  0 - 6   Sunday 0 or 7                                    command to be executed                   minutetestcmd  2015-10-21 07 28 00  42  amp  amp  command   with minutetestcmd defined as     usr bin env bash starttime   date -d   1     s     return UTC time now   date    s     get the amount of minutes  using integer division to avoid lag  minutes      now - starttime    60      set the modulo modulo  2   do the test    now  gt   starttime     amp  amp     minutes   modulo    0      Remark  UNIX time is not influenced by leap seconds  Remark  cron has no sub-second accuracy

[php] How to run a cronjob every X minutes?

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