Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: Delete Blank Lines Between DHCP Host Blocks
Top Forums Shell Programming and Scripting Delete Blank Lines Between DHCP Host Blocks Post 302258695 by cstovall on Saturday 15th of November 2008 11:39:21 AM
Old 11-15-2008
Bug Delete Blank Lines Between DHCP Host Blocks
Hi All,

I have a dhcpd.conf file that gets static hosts added and removed via a shell script. After sometime, there becomes huge gaps of space ( blank lines ) between each host block. I tried a couple of sed one-liners; but, I can't seem to get the output I'm looking for. Also, I would like to delete the blank lines between the host blocks interactively instead of piping to a file then doing a move back to the original file. Below is the output I'm looking for:

old dhcpd.conf:

host example1 {
hardware ethernet 00:00:00:00:00:01;
fixed-address 192.168.135.2;
option subnet-mask 255.255.255.0;
option routers 192.168.135.1;
next-server 192.168.135.210;
filename "linux-install/pxelinux.0";
}


host example2 {
hardware ethernet 00:00:00:00:00:02;
fixed-address 192.168.135.3;
option subnet-mask 255.255.255.0;
option routers 192.168.135.1;
next-server 192.168.135.210;
filename "linux-install/pxelinux.0";
}

host example3 {
hardware ethernet 00:00:00:00:00:03;
fixed-address 192.168.135.4;
option subnet-mask 255.255.255.0;
option routers 192.168.135.1;
next-server 192.168.135.210;
filename "linux-install/pxelinux.0";
}



new dhcpd.conf file:

host example1 {
hardware ethernet 00:00:00:00:00:01;
fixed-address 192.168.135.2;
option subnet-mask 255.255.255.0;
option routers 192.168.135.1;
next-server 192.168.135.210;
filename "linux-install/pxelinux.0";
}
host example2 {
hardware ethernet 00:00:00:00:00:02;
fixed-address 192.168.135.3;
option subnet-mask 255.255.255.0;
option routers 192.168.135.1;
next-server 192.168.135.210;
filename "linux-install/pxelinux.0";
}
host example3 {
hardware ethernet 00:00:00:00:00:03;
fixed-address 192.168.135.4;
option subnet-mask 255.255.255.0;
option routers 192.168.135.1;
next-server 192.168.135.210;
filename "linux-install/pxelinux.0";
}


Any help would be greatly appreciated. Thanks in advance!
 

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

delete blank lines or lines with spaces only

hi there i'm trying to delete blank lines and or lines with spaces only from a series of files in an directory. to do so, i'm using this: for files in `ls /users/myname/pesop* 2>/dev/null` do grep -v ^$ $files > newfile mv newfile $files done now, this works great for blank lines but... (3 Replies)
Discussion started by: vascobrito
3 Replies

2. Shell Programming and Scripting

delete blank lines with sed

I have a text file with blank lines fullfilled with spaces and others only containing the "Enter" caracter, the \012. I would like to eliminate all them with the sed command. Is it possible? making: sed '/^$/d' <file should delete the blank lines but doesn't work for the lines that only... (2 Replies)
Discussion started by: tmxps
2 Replies

3. UNIX for Dummies Questions & Answers

delete blank lines from a file

can anyone show me how to delete blank lines from a file. thanks in advance (2 Replies)
Discussion started by: sachin.gangadha
2 Replies

4. Shell Programming and Scripting

Delete blocks of lines from text file

Hello, Hello Firends, I have file like below. I want to remove selected blocks say abc,pqr,lst. how can i remove those blocks from file. zone abc { blah blah blah } zone xyz { blah blah blah } zone pqr { blah blah blah } (4 Replies)
Discussion started by: nrbhole
4 Replies

5. UNIX for Dummies Questions & Answers

delete traling blank lines only

Hi, I have blank line in the file, I just want to remove trailing blank lines. There are some blank lines between the lines, i don't want remove those. Just want to delete blank lines at the end. I used this command sed '/^$/d' infile > outfile, but it is not removing anything. I think... (1 Reply)
Discussion started by: visu
1 Replies

6. Shell Programming and Scripting

Why cant i delete blank lines?

I have a sed pipeline: myVar=$(cat $FILE | sed -n '/regex/,/regex/{/regex/d;p}' | sed -n '/regex/!p' | sed -e s/*:// | sed /regex/,+8d \ ) sed '/^$/d' sed '/./!d' And i've tried to add that in a different order rather then just on the end..Why isnt it deleting all the blank... (2 Replies)
Discussion started by: omgsomuchppl
2 Replies

7. Shell Programming and Scripting

Delete blank lines from a file

Hi, I want to use diff to compare two files in a Perl file. But one of the files has some blank lines at the end. So I want to delete the blank lines from the file firstly and then use diff to compare them. But I dont know how to delete the blank lines from the files. Meanwhile, the system is... (5 Replies)
Discussion started by: Damon_Qu
5 Replies

8. Shell Programming and Scripting

Delete blank lines, if blank lines are more than one using shell

Hi, Consider a file named "testfile" The contents of file are as below first line added for test second line added for test third line added for test fourth line added for test fifth line added for test (5 Replies)
Discussion started by: anil8103
5 Replies

9. UNIX for Advanced & Expert Users

Delete blank spaces and blank lines in a file

Hi Gurus, Somebody can say me how to delete blank spaces and blank lines in a file unix, please. Thank you for advanced. (10 Replies)
Discussion started by: systemoper
10 Replies

10. UNIX for Beginners Questions & Answers

Delete multiple lines between blank lines containing two patterns

Hi all, I'm looking for a way (sed or awk) to delete multiple lines between blank lines containing two patterns ex: user: alpha parameter_1 = 15 parameter_2 = 1 parameter_3 = 0 user: alpha parameter_1 = 15 parameter_2 = 1 parameter_3 = 0 user: alpha parameter_1 = 16... (3 Replies)
Discussion started by: ce9888
3 Replies

LEARN ABOUT DEBIAN

vlan-interfaces

VLAN-INTERFACES(5)						   File formats 						VLAN-INTERFACES(5)

NAME

       /etc/network/interfaces (vlan) - vlan extensions for the interfaces(5) file format

DESCRIPTION

       /etc/network/interfaces	contains  network  interface  configuration  information  for  the  ifup(8)  and ifdown(8) commands.  This manpage
       describes the vlan extensions to the standard interfaces(5) file format.

       Primary extensions exist to make and destroy vlan interfaces, secondary extensions exist for ipv4 interface manipulation which  are  gener-
       ally needed when using (a lot of) vlans.

VLAN CREATION

       Vlan  interface	definitions  exist  of the vlan interface name, and an optional 'raw-device' parameter.  Vlan interfaces are numbered 1 to
       4095.  You have the option to have interface names zero-padded to 4 numbers, or just the plain digits without leading zero.  The  following
       example shows four ways to create a vlan with id 1 on interface eth0.  They all result in different names.

	iface eth0.1 inet static
	    address 192.168.1.1
	    netmask 255.255.255.0

	iface vlan1 inet static
	    vlan-raw-device eth0
	    address 192.168.1.1
	    netmask 255.255.255.0

	iface eth0.0001 inet static
	    address 192.168.1.1
	    netmask 255.255.255.0

	iface vlan0001 inet static
	    vlan-raw-device eth0
	    address 192.168.1.1
	    netmask 255.255.255.0

	# We don't have br support out of the box
	iface br0.2 inet static
	    vlan-raw-device br0
	    address 192.168.1.1
	    netmask 255.255.255.0

	# Aliases are ignored
	iface br0.2:1 inet static
	    address 192.168.1.1
	    netmask 255.255.255.255

EXTRA IFACE OPTIONS

       Usually someone who uses vlans also wants to do some other manipulations with the ip stack or interface.

       vlan-raw-device devicename
	      Indicates the device to create the vlan on.  This is ignored when the devicename is part of the vlan interface name.

       ip-proxy-arp 0|1
	      Turn proxy-arp off or on for this specific interface.  This also works on plain ethernet like devices.

       ip-rp-filter 0|1|2
	      Set the return path filter for this specific interface.  This also works on plain ethernet like devices.

       hw-mac-address mac-address
	      This sets the mac address of the interface before bringing it up.  This works on any device that allows setting the hardware address
	      with the ip command.

AUTHOR

       This manpage was adapted from interfaces(5) by Ard van Breemen <ard@kwaak.net>

SEE ALSO

       vconfig(8) interfaces(5)

vlan								 September 30 2007						VLAN-INTERFACES(5)
All times are GMT -4. The time now is 08:51 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy