replacing a line with sed command

praveen1461996 · 06-21-2019, 05:15 AM

hello ,

i am trying to replace below line using sed

username="test" password="something"

my command is
sed -i -e 's/username=".*"/username="'$username'"/.*\./password=".*"/password="'$password'"/g' server.xml

it is updating username but removing password session from the line

syg00 · 06-21-2019, 05:24 AM

Regex here is greedy - it will look to match the longest string. So the first ".*" will match from the first double quote until the last double quote at the very end - so will wipe out everything after the first equals sign.
You need to be more specific with the pattern.

praveen1461996 · 06-21-2019, 05:31 AM

so , can i expect the correct syntax to solve the issue

username and password are variables here

how can i pass variables here

Turbocapitalist · 06-21-2019, 06:03 AM

Get the syntax correct first. Then look at fixing the patterns. See also the -r option in the manual page via "man sed" Then look at adding shell variables.

The correct syntax is s///; for each substitution.
The pattern you probably need would be "[^"]+"
Then for the shell variables, modify the quoting. Quotes must be escaped when included inside quotes of like kind.

Also, it will save trouble to specify a backup file: -i.bak or -i.orig or something along those lines.

MadeInGermany · 06-22-2019, 01:16 AM

.* is any characters; replace with [^"]* (any characters but quote) to not span over a quote.

Code:

sed -i 's/username="[^"]*"/username="'"$username"'"/; s/password="[^"]*"/password="'"$password"'"/' server.xml

In command arguments have $variables in quotes when the shell should not attempt substitutions on it.