Updating Property Files using Shell Script

Recently, one of my colleagues asked me some hints on how to read updated properties from one property file, search the same property in the target property file (files) and update/replace the corresponding property value (s) in the target property file (s) if property key matches. He wanted to do this operation using just the regular shell script, so No ANT or Java or Perl. I've put together a simple script file for him and decided to publish it here so that other people with similar needs can be benefited as I did not find any other similar posting.


Let's say, here is how the source property file looks like:

--------- sFile.properties --------

# Updated property values connection.username=mssqluser connection.password=********* connection.hostname=thishost.domain connection.time.format=yyyy-MM-dd HH:mm:ss

Let's say, here is how one of the target property files looks like:

--------- tFile.properties --------

# Connection properties connection.username=xyz connection.password=abc456789 connection.hostname=localhost connection.time.format =yyyy-MMM-dd HH:mm:ss

Here is how the shell script file look like:

---------- propertyUpdater.sh ------

#!/bin/bash # Source input property file that provides new/updated property values. sFile='/cygdrive/c/temp/Bscripts/sFile.properties' # Target directory where multiple property files whose property value(s) need to be updated/replaced. tDir='/cygdrive/c/temp/Bscripts/props' # Reads each line and assigns value to variable _line, excluding all commented (starting with #) lines and all empty lines for _line in `cat "$sFile" | grep -v -e'#' | grep -v -e'^$'`; do     echo "Reading line: $_line from source file: $sFile"     _key=`echo $_line | cut -d '=' -f1`     _value=`echo $_line | cut -d '=' -f2`     echo "Retrieved property key: $_key with value: $_value"     # Comment following 'for' loop if you are using 'tFile' variable.     for _file in `find $tDir -type f -print | grep ".properties$"`; do        echo "Updating target property file: $tDir/$_file"        sed -i "s/^$_key=.*/$_line/g" "$tDir/$_file"        # for those properties which have space between key and '=' sign.        sed -i "s/^$_key[ \t]=.*/$_line/g" "$tDir/$_file"     done    done

--------- tFile.properties after the update -----

# Connection properties connection.username=mssqluser connection.password=********* connection.hostname=thishost.domain connection.time.format=yyyy-MM-dd HH:mm:ss

Hope, it helps!