Hi All,

I want to delete a node from a file say node.txt

CREATE NODE abc
OP-SYSTEM UNIX
SYS-NAME abc
LOCAL-REPOSITORY /usr/adm/best1_default/collect
TRANSFER AUTOMATIC

CREATE NODE xyz
OP-SYSTEM UNIX
SYS-NAME xyz
LOCAL-REPOSITORY /usr/adm/best1_default/collect
TRANSFER AUTOMATIC

CREATE NODE pqr
OP-SYSTEM UNIX
SYS-NAME pqr
LOCAL-REPOSITORY /usr/adm/best1_default/collect
TRANSFER AUTOMATIC

Following sed command will delete node xyz

bash$ sed '/CREATE NODE xyz/,/TRANSFER AUTOMATIC/d' node.txt

o/p:
CREATE NODE abc
OP-SYSTEM UNIX
SYS-NAME abc
LOCAL-REPOSITORY /usr/adm/best1_default/collect
TRANSFER AUTOMATIC

CREATE NODE pqr
OP-SYSTEM UNIX
SYS-NAME pqr
LOCAL-REPOSITORY /usr/adm/best1_default/collect
TRANSFER AUTOMATIC

But when I take node name in variable and use variable in sed command, its not working.

bash$ node=xyx
bash$ sed '/CREATE NODE $node/,/TRANSFER AUTOMATIC/d' node.txt

I would really appreciate your help.

Use double quotes (") instead of single quotes ('). Only within double quotes variables get evaluated. In single quotes they are taken literaly.

1 members found this post helpful.

Thanks a lot zhjim. It worked

You're welcome. Please mark thread as solved. See top of the page under "Thread Tools". Thanks.

I have 2 more problems with this script and want help to resolve them

Number 1

The files I am working on contain the nodes in below format, However there are some nodes where I see only one space between CREATE NODE and server name (e.g. abc) while as some have multiple spaces. I would like to know how i can overcome this problem.

CREATE NODE xyz
OP-SYSTEM UNIX
SYS-NAME xyz
LOCAL-REPOSITORY /usr/adm/best1_default/collect
TRANSFER AUTOMATIC

Command used: bash$ sed "/CREATE NODE $node/,/TRANSFER AUTOMATIC/d" node.txt ( it will delete the above node (xyz) because it has only one space) but it wont delete if node is configued in below format:

CREATE NODE xyz
OP-SYSTEM UNIX
SYS-NAME xyz
LOCAL-REPOSITORY /usr/adm/best1_default/collect
TRANSFER AUTOMATIC

I want this command to delete the node irrespective of the no of spaces between CREATE NODE and Node Name (xyz)

Number 2

Also when i delete multiple servers from a single file it leaves 2 blank lines after every node name i would like to leave only one blank line after every node name

Current State

CREATE NODE abc
OP-SYSTEM UNIX
SYS-NAME abc
LOCAL-REPOSITORY /usr/adm/best1_default/collect
TRANSFER AUTOMATIC

CREATE NODE xyz
OP-SYSTEM UNIX
SYS-NAME xyz
LOCAL-REPOSITORY /usr/adm/best1_default/collect
TRANSFER AUTOMATIC

CREATE NODE pqr
OP-SYSTEM UNIX
SYS-NAME pqr
LOCAL-REPOSITORY /usr/adm/best1_default/collect
TRANSFER AUTOMATIC

Suppose i want to delete node name "xyz" it would leave 2 blank lines(line above node and line below node), I would like to leave only one blank line. Please suggest can it be done using the same command.

Lets start with problem 2. Think about what you delete. You leave the empty line after "TRANSFER AUTOMATIC". Either use something like
Also not sure if this will work. Or after deleting use tr -s '\n' when done. You might also search the net for "sed removing double empty lines".

Regarding your first problem you have to adjust your regex.

1 members found this post helpful.

Thanks for response zhjim. sed '/^$/N;/^\n$/D' will remove double lines. Just for curiosity, I tried to delete all the lines in between CREATE NOTE $node and next blank line (including blank line). I came up with following sed command:

/usr/bin/sed "/CREATE NODE *$node_name/,/""/d" node.txt

But don't know why it is deleting everything from CREATE NODE $node_name to the end of the file. I would really appreciate your help here.