How to extract hostname from file using awk?

Shell Programming and Scripting
1

Hi

iam having file with below lines of text

[local]pun-ras-bng-mhs-01#cont bsnl.in
[local]enk-ras-bng-cse-01#cont bsnl.in

how to extract the host name and store in a variable and to print output using awk command

output will be

HOSTNAME
pun-ras-bng-mhs-01
enk-ras-bng-cse-01

Tnx in advance.

2

Here is how you can get the hostname in between "]" and "#"

awk -vRS="#" 'RT{gsub(/.*]/,"");print}' filename

3

Hi below error is coming after executing the script

root@blr-svr-oclan-01 # awk -vRS="#" 'RT{gsub(/.*]/,"");print}' x 
awk: syntax error near line 1
awk: bailing out near line 1
root@blr-svr-oclan-01 #
4

If you are in Solaris, use nawk instead of awk

5

iam using solaris 10.the code given is running with nawk with out any error
but no output displayed

root@blr-svr-oclan-01 # more x
[local]pun-ras-bng-mhs-01#cont bsnl.in
[local]enk-ras-bng-cse-01#cont bsnl.in
root@blr-svr-oclan-01 # nawk -vRS="#" 'RT{gsub(/.*]/,"");print}' x 
root@blr-svr-oclan-01
6

As I'm not sure what "RT" in the awk program stands for (being an uninitialized and thus empty variable prohibiting the print), try this small modification of ./hari.sh's script:

$ awk -vFS="#" 'BEGIN{print "HOSTNAME"} {gsub(/.*]/,"");print $1}' file
HOSTNAME
pun-ras-bng-mhs-01
enk-ras-bng-cse-01

Use nawk, of course...

7

Hi

its working with nawk but output not as desired. extra words are coming in output

root@blr-svr-oclan-01 # nawk -vFS="#" 'BEGIN{print "HOSTNAME"} {gsub(/.*]/,"");print $1}' x

output

HOSTNAME
pun-ras-bng-mhs-01#cont
enk-ras-bng-cse-01#cont
8 
awk -F'[]#]' '{print $2}' file
9

Hi

not getting output as desired.

root@blr-svr-oclan-01 # awk -F'[]#]' '{print $2}' x

output

  
local]pun-ras-bng-mhs-01#cont bsnl.in
local]enk-ras-bng-cse-01#cont bsnl.in
root@blr-svr-oclan-01 #

Required output will be

  
HOSTNAME
pun-ras-bng-mhs-01
enk-ras-bng-cse-01
10
11

Hi

if iam using nawk. no output is coming

root@blr-svr-oclan-01 # nawk -F'[]#]' '{print $2}' x
12

On Solaris use /usr/xpg4/bin/awk rather than awk or nawk

1 Like
13

Hi,

now code is working fine.

root@blr-svr-oclan-01 # /usr/xpg4/bin/awk -F'[]#]' '{print $2}' x
pun-ras-bng-mhs-01
enk-ras-bng-cse-01
root@blr-svr-oclan-01 #

tnx

14

there are many ways to achieve desired target

<filename cut -d] -f2 | cut -d'#' -f1

awk -F'[]#]' '{ print $2 }' filename

sed 's/.*]\|#.*//g' filename

perl -pe 's/.*\]|#.*//g' filename