LinuxQuestions.org - Delete a line from a file

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Delete a line from a file

Hi guys,

How do i write a script which will delete a perticular line from a file starting with "shell" word.

what have you learnt till now since you started 70 posts ago? Put in some effort and show us some code. I ask because this is a very simple task.

what is the script? code??

I m explaining in detail.

Below is the content of my file called vm.cfg.
I need to delete a line starting from disk word so when i write
sed "/^disk/d" vm.cfg
It only delete the line
disk = ['file:/var/ovs/mount/93B14928C7A6438284753B2F2AB197BB/seed_pool/vm_temp
and not
/System.img,hda,w',
'file:/OVS/iso_pool/winxpsp2/WXPVOL_EN.iso,hdc:cdrom,r',
]
How can i establish this.

Code:

[root@OVM-SERVER1 vm_temp]# cat vm.cfg

acpi = 1

apic = 1

builder = 'hvm'

device_model = '/usr/lib/xen/bin/qemu-dm'

disk = ['file:/var/ovs/mount/93B14928C7A6438284753B2F2AB197BB/seed_pool/vm_temp/System.img,hda,w',

'file:/OVS/iso_pool/winxpsp2/WXPVOL_EN.iso,hdc:cdrom,r',

]

kernel = '/usr/lib/xen/boot/hvmloader'

memory = '300'

name = 'vm_temp'

on_crash = 'restart'

on_reboot = 'restart'

pae = 1

serial = 'pty'

timer_mode = '0'

usbdevice = 'tablet'

uuid = '8569c556-fdf9-41f7-93f4-52350560b13c'

vcpus = 1

vif = ['bridge=xenbr0,mac=00:16:3E:64:FB:D3,type=ioemu']

vif_other_config = []

vnc = 1

vncconsole = 1

vnclisten = '0.0.0.0'

vncpasswd = 'oracle'

vncunused = 1

there are many ways beside sed to delete a line, here's one other way.

Code:

$ awk '!/^disk/' file > newfile

I suggest you start learning awk from now on. see my sig

Quote:

Originally Posted by ghostdog74 (Post 3745375)

there are many ways beside sed to delete a line, here's one other way.

Code:

$ awk '!/^disk/' file > newfile

I suggest you start learning awk from now on. see my sig

disk = ['file:/var/ovs/mount/93B14928C7A6438284753B2F2AB197BB/seed_pool/vm_temp/System.img,hda,w',
'file:/OVS/iso_pool/winxpsp2/WXPVOL_EN.iso,hdc:cdrom,r',
]
Thanks for your help but.
I want to write a program which will delete above mentioned set of lines.

There will be no SED vs. AWK wars.......;)

Have you read a tutorial on SED? I ask this because you used an address/action statement earlier---what you need is an address range, like so:

Code:

sed '/start/,/finish/ d'  ##deletes all lines, beginning with on containing "start", and ending on one containing "finish".



sed '/start/,+3 d'  ##as above, but deletes 3 lines after the first address

Best SED tutorial here:
http://www.grymoire.com/Unix/Sed.html

Quote:

Originally Posted by pinga123 (Post 3745385)

Code:

$ awk '/^disk/{f=1}f&&!/\]/{next}f&&/\]/{f=0}f==0' file

Code:

$ awk '/disk/,/\]/{next}1' file