shell script sed replace

Question

I have this file config.xml

<widget id="com.example.hello" version="0.0.1">
<name>HelloWorld</name>
<description>
    A sample Apache Cordova application that responds to the deviceready event.
</description>
<author email="dev@callback.apache.org" href="http://cordova.io">
    Apache Cordova Team
</author>
 <enter>PASSWORD</enter>
<content src="index.html" />
<access origin="*" />

I tried to do it with sed without success.

I need to do this:

$./script.sh config.xml NEWPASSWORD

to get:

<widget id="com.example.hello" version="0.0.1">
<name>HelloWorld</name>
<description>
    A sample Apache Cordova application that responds to the deviceready event.
</description>
<author email="dev@callback.apache.org" href="http://cordova.io">
    Apache Cordova Team
</author>
 <enter>NEWPASSWORD</enter>
<content src="index.html" />
<access origin="*" />

Answer 1

Using backreference:

sed "s/^\( *<enter>\)\([^>]*\)</\1$2</" "$1"

• ^\\( *<enter>\\) : search for lines starting with any number of spaces followed by <enter> . Matching characters are captured with escaped parentheses.

• \\([^>]*\\)< : following characters up top next < are captured in a second group.

• \\1$2< : in the substitution string, characters from first group are output( \\1 ) followed by the second parameter value passed to the script, ( $2 , the new password value)

The command is applied to $1 , the file passed as first parameter to the script (the file name).

To edit the file in place, use the -i flag:

sed -i "s/^\( *<enter>\)\([^>]*\)</\1$2</" "$1"

Answer 2

The good result is:

$cat script.sh

#!/bin/sh
file=$1
sed -i "s/^\( *<enter>\)\([^>]*\)</\1$2</" "$1"

Then:

$./script.sh config.xml NEWPASSWORD

Many thanks to everyone, especially to Kenavoz.