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If pattern match, replace it with #

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Top Forums Shell Programming and Scripting If pattern match, replace it with #
# 1  
Old 07-20-2017
If pattern match, replace it with #
This command is not working for me.
Code:
awk '{if ($1 == server) {$1 = #server} }'  /etc/ntp.conf

Code:
# grep server /etc/ntp.conf
# Use public servers from the pool.ntp.org project.
server 0.rhel.pool.ntp.org iburst
server 1.rhel.pool.ntp.org iburst
server 2.rhel.pool.ntp.org iburst
server 3.rhel.pool.ntp.org iburst
#broadcast 192.161.255 autokey        # broadcast server

Output:
Code:
# grep server /etc/ntp.conf
# Use public servers from the pool.ntp.org project.
#server 0.rhel.pool.ntp.org iburst
#server 1.rhel.pool.ntp.org iburst
#server 2.rhel.pool.ntp.org iburst
#server 3.rhel.pool.ntp.org iburst
server ntpserver.com
server  127.127.1.0     # local clock

#broadcast 192.161.255 autokey        # broadcast server

Last edited by RudiC; 07-21-2017 at 01:46 AM.. Reason: Moved code tag.
# 2  
Old 07-20-2017
Literal strings must be in "quotes". Also you certainly want to explicitly print.
Code:
awk '{if ($1 == "server") {$1 = "#server"} print}'  /etc/ntp.conf

Another solutions
Code:
awk '{if ($1 == "server") {print "#"$0} else {print} }'  /etc/ntp.conf

Code:
awk '{if ($1 == "server") {printf "#"} print}'  /etc/ntp.conf

This User Gave Thanks to MadeInGermany For This Post:
kenshinhimura
# 3  
Old 07-20-2017
You forgot these two.. also awk wont save the file permanently.


Code:
#server 3.rhel.pool.ntp.org iburst
server ntpserver.com
server  127.127.1.0     # local clock

# 4  
Old 07-21-2017
You forgot to specify WHAT you want exactly.
# 5  
Old 07-21-2017
Howsoever, try
Code:
awk '
/^server/       {$1 = "#" $1
                }
/#broadcast /   {print "server ntpserver.com"
                 print "server  127.127.1.0     # local clock"
                 print ""
                }
1
'  /etc/ntp.conf

, save the result to a temp file, and then cp or mv that back to /etc/ntp.conf (as shown umpteen times in these fora).
This User Gave Thanks to RudiC For This Post:
kenshinhimura
# 6  
Old 07-21-2017
The following uses a stage variable met that controls where to insert the new text. If there was no match encountered (met==0) or the new text was not yet inserted (met==1), it inserts the new text at the END. Therefore the new text insertion is put into a function printnew().
Code:
awk '
function printnew() {
  print "server ntpserver.com"
  print "server 127.127.1.0 # local clock"
}
{
  if ($1 == "server") {
    print "#"$0
    if (met==0) met=1
  } else {
    print
    if (met==1) {
      print
      printnew()
      met=2
    }
  }
}
END {
  if (met<2) printnew()
}
' /etc/ntp.conf

This User Gave Thanks to MadeInGermany For This Post:
kenshinhimura
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