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I'm searching for a reliable way to test if postfix is running from inside a bash script.

My first attempt was simply trying pidof postfix, which doesn't work.

Then I tried to get the postfix status:

POSTFIX_LOCATION=/var/packages/MailServer/target/sbin/postfix # location of postfix
result=`$POSTFIX_LOCATION status`
if [ -z $result ]; then
    echo "Error: No status output from postfix"
elif [[ "$result" == *"is running"* ]]; then
    echo "postfix is running!"
else echo "postfix is not running!"
fi

But even though the status is reported to the console, the result variable stays empty. This is the console output:

postfix/postfix-script: the Postfix mail system is running: PID: 11996
Error: No status output from postfix

I finally found a way to test if postfix is running by getting the process name of PID: 11996, which is "master". So the following does work:

pidof master

But this is not very verbose and I'm not sure if this is a reliable way to test if postfix is running.

So my questions are:

  • How can I get the output of postfix status from inside a bash script? - Anything I'm doing wrong there?
  • Is there a better reliable way to test if postfix is running from inside a bash script?
Balder
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    Possible `status` outputs to `stderr`? Try to add `2>&1` to `status`-command. Also you can use `pgrep postfix` – Costas Feb 28 '15 at 07:52
  • I tried `2>&1` but the result stays empty. Sadly `pgrep` is no option because it is not available on the system (a Synology disk station with DSM 5.1). – Balder Feb 28 '15 at 08:05
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    Does http://stackoverflow.com/questions/226699/how-to-monitor-postfix-mta-status help? – garethTheRed Feb 28 '15 at 08:33
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    `ps aux | grep [p]ostfix` ? – Costas Feb 28 '15 at 08:41
  • Thanks @Costas and @garethTheRed - using `ps` seems to work. On the DSM system `ps` doesn't accept any parameters other then `w`. But simply calling `ps | grep [p]ostfix` does work. – Balder Feb 28 '15 at 08:49
  • Maybe by getting the status from /ezc/init – user236012 Feb 28 '15 at 11:23

6 Answers6

19

Debian or Ubuntu

sudo service postfix status
Javo Troya
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4

A reliable way to test if postfix is running:

if /var/packages/MailServer/target/sbin/postfix status; then
    echo "postfix is running!"
else echo "postfix is not running!"
fi

An alternative that essentially does the same:

if /var/packages/MailServer/target/libexec/master -t 2>/dev/null; then
    echo "postfix is not running!"
else echo "postfix is running!"
fi

Reasoning

After doing some more research, it turned out that testing for ps | grep [p]ostfix is not reliable at all to verify if postfix is running.

It seems the reason why /var/packages/MailServer/target/sbin/postfix status does not output anything useful is, because postfix uses the internal postlog binary for the output. The relevant code can be found in the bash script /var/packages/MailServer/target/libexec/postfix-script:

LOGGER="$command_directory/postlog -t $MAIL_LOGTAG/postfix-script"
INFO="$LOGGER -p info"

Checking for the exit code of postfix status does work fine on the other hand. The postfix-script is actually called behind the scenes by the postfix binary and cannot be called directly. But luckily the script also includes the code to test if postfix is running:

status)
    $daemon_directory/master -t 2>/dev/null && {
        $INFO the Postfix mail system is not running
        exit 1
    }
    $INFO the Postfix mail system is running: PID: `sed 1q pid/master.pid`
    exit 0
    ;;

The variable $daemon_directory gets set by the calling postfix binary. On my system it resolves to /var/packages/MailServer/target/libexec/.

Balder
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4

To check whether Postfix is running or not:

sudo /etc/init.d/postfix status

To start the Postfix:

sudo /etc/init.d/postfix start

To stop the postfix:

sudo /etc/init.d/postfix stop
Rui F Ribeiro
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Sandesh
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    I can type `postfix start` without an error message, but when I type `postfix status` it says "the Postfix mail system is not running." I suppose it's silently failing. – PJ Brunet Feb 11 '17 at 19:14
1

You can use the is-active command:

if (systemctl is-active -q postfix); then
  echo "Success: postfix is running."
else
  echo "Error: postfix is not running!"
fi

Here's the documentation for 'is-active'.

consuela
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0

I'm running postfix inside a very lean docker container and has very few normal commands installed. Yet it does have netstat. So use netstat to list ports that a process is listening on. Look for a process listening on the smtp port (e.g. postfix).

if ! netstat -l | grep smtp; then
    echo "postfix is not running!"
else echo "postfix is running!"
fi
Bryan
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    Can't you just do `if postfix status; then echo running; fi`? You shouldn't need any other command than `postfix` here as `postfix` itself can tell its own service status. – Stéphane Chazelas Oct 31 '20 at 17:27
  • Stéphane Chazelas is correct and all the other dances are not needed. Thanks Stéphane – Bryan Nov 25 '20 at 14:42
0

I believe the suggested solutions with "master -t" and "postfix status" may incorrectly report that postfix is running if it was previously killed forcibly leaving its PID files behind.

"pidof master" and similar ps/grep manipulations are fine, except there might be other processes called "master".

So "sudo service postfix status" might be the best (except OP is running DSM where this is not applicable).

Egor Emeliyanov
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