please explain

[Paul Howarth]

Deepak Oberoi wrote:
> Thanks very much paul
> that was a big help!
> but i still cant make any sense out of these ones..
> 
> 
> 48: if ! test -f /var/run/sm-client.pid ; then

if the file /var/run/sm-client.pi does not exist (see "man test")

> 49: echo -n $"Starting sm-client: "

Write "Starting sm-client: " to screen

> 50: touch /var/run/sm-client.pid

Create empty file /var/run/sm-client.pid

> 51: chown smmsp:smmsp /var/run/sm-client.pid

And change its ownership to user smmsp, group smmsp. This is done because the 
sendmail Message Submission Program (used for sending mail from your machine) 
runs as un unprivileged user and group smmsp, and would not otherwise have 
permission to create a file in directory /var/run

> 52: daemon --check sm-client /usr/sbin/sendmail -L sm-msp-queue -Ac \
> 53: -q $SMQUEUE $SENDMAIL_OPTARG

Start another instance of sendmail, writing log entries (/var/log/maillog) 
with tag "sm-msp-queue" (-L sm-msp-queue), running as the Message Submission 
Program (-Ac), processing the submission queue every $SMQUEUE time period (-q 
$SMQUEUE), and with other options defined by $SENDMAIL_OPTARG

> 54: RETVAL=$?
> 55: echo
> 56: [ $RETVAL -eq 0 ] && touch
> /var/lock/subsys/sm-client

As before.

The Message Submission Program takes mail generated locally and submits it to 
the main sendmail server (started earlier in the initscript) for sending to 
its ultimate destination. Two instances of sendmail, running as different 
users, are used for security reasons.

Paul.