UNIX for Dummies Questions & Answers

Hi,

I am trying to write a script which will modify a given account's settings by searching for a line in a file and then replacing the line after it. Here is a portion of my input file:

[0002]
type=friend
username=0002
secret=password
host=dynamic
dtmfmode=rfc2833
mailbox=0002
context=sip
insecure=very
canreinvite=no
nat=yes
realm=192.168.1.122
callerid="Phone2id" <0002>

[0003]
type=friend
username=0003
secret=password
host=dynamic
dtmfmode=rfc2833
mailbox=0003
context=sip
insecure=very
canreinvite=no
nat=yes
realm=192.168.1.122
callerid="Phone3id" <0003>

I want to replace "password". I want to match the line before "secret=password" to be sure it is changing the correct line as the username will be a unique identifier.

I have been trying to do this with sed but have not been able to make it work. Also, I am not limited to sed.

if you know the username and the file always has each account separated by a blank line and the secret entry always follows the username entry.

Code:

sed '/username=0003/,/^$/s/secret=.*/secret=<newpassword>/' file > output_file

if you want to change a list of username:secret entries from an input file. the -i switch will update the file inplace so make a backup first

Code:

# content of input file
0002:newpwd002
0003:newpwd003

IFS=":"
while read name pwd;do
  sed -i "/username=$name/,/^$/s/secret=.*$/secret=$pwd/" account_file
done < input

thanks a bunch! the sed line was just what I needed!