Shell Script - Update Fields in plist/xml (data serialization) file - after specific field match - using awk
We face the need to update the XML, where tag value or key-value pairs needs to be modified, using shell script. Tried the below way:
Say XML file appears like:
<?xml version="1.0" encoding="UTF-8"?>
<key>Server</key>
<lex>
<key>Location</key>
<string>Homestead</string>
<key>days</key>
<integer>60</integer>
</lex>
<key>server</key>
<lex>
<key>host</key>
<string>ab.host.com</string>
<key>days</key>
<integer>30</integer>
</lex>
Say XML file appears like:
<?xml version="1.0" encoding="UTF-8"?>
<key>Server</key>
<lex>
<key>Location</key>
<string>Homestead</string>
<key>days</key>
<integer>60</integer>
</lex>
<key>server</key>
<lex>
<key>host</key>
<string>ab.host.com</string>
<key>days</key>
<integer>30</integer>
</lex>
Now we want to update the field host value. The below script call can do it:
./updatexml.sh bcd.host.com
where updatexml.sh looks like:
#! /bin/bash
var=$1
awk -F'[<>]' '
/<key>Client<\/key>/ {
f = 1
}
/<key>host<\/key>/ {
s = 1
}
{
if (f && s && /<value>/) {
sub($3,"'$var'",$0);
f = 0
s = 0
}
print
}
' 1.xml > temp.xml
mv temp.xml 1.xml
Explanation:
set a flag 'f', after the occurrence of the tag "<key>Client</key>" and on finding occurrence of "<key>host</key>" set another flag. Then it is self explicable, on match of both flags true and tag <value> we replace the third column of line with variable.
