How to read a .properties file through script

[rahulJ james]

I have a appl.properties file with a key value pair. I just wanted to use 2 values from the properties file in my script.

Assume I have name=jack and age=50 in my appl.properties file and in my script I have variables with values like #name# and #age#.

I have to get the value of the key "name" and "age" from the properties file and replace the strings #name# and #age# which I have it in my script.

Can anyone advise

[Tim Holloway]

The easy way to do it is to note that a Java properties file has the same format as a basic shell script.

However, there's a trick to it. If you just run the properties file like so:

sh appl.properties

The assignments will be made at the sub-level, then discarded when the properties file (script) ends execution.

So to get the properties in a calling script, you need to use the "source" command:

. appl.properties

Note that the space after the initial dot is very important!

To reference shell variable assignments, you use the "$" to indicate variable substitution.

So, to put it all together:

#!/bin/sh
# Sample shell script to read and act on properties
 
# source the properties:
. appl.properties
 
# Then reference then:
echo "My name is $name and I'm $age years old."

[java cousin]

You are ausome !!

[Jesper de Jong]

"java cousin", please check your private messages. You can see them by clicking My Private Messages.

[sameer sood]

This will require making properties file executable any other suggestions ?

[sameer sood]

PLease help

. filename

prints all on screen , anyway to stop it ??

[Joshua Davis]

Tim Holloway wrote:The easy way to do it is to note that a Java properties file has the same format as a basic shell script.

However, there's a trick to it. If you just run the properties file like so:

sh appl.properties

The assignments will be made at the sub-level, then discarded when the properties file (script) ends execution.

So to get the properties in a calling script, you need to use the "source" command:

. appl.properties

Note that the space after the initial dot is very important!

To reference shell variable assignments, you use the "$" to indicate variable substitution.

So, to put it all together:

#!/bin/sh
# Sample shell script to read and act on properties
 
# source the properties:
. appl.properties
 
# Then reference then:
echo "My name is $name and I'm $age years old."

This solution is good because it's simple, but it will only work if you have Java properties file that doesn't have any property names or values that have special characters (to shell) in them. For example, if there is a property with a '.' in the name, then this solution won't work. That's the case for most Java properties files I've used, especially those used with ANT.

Here is a properties file that Java can read, but bash can't:

# this is a java properties file
one=fred
prop.two=this is property two

The second property is going to cause problems because it has a dot in the name, as well as having spaces in the value. Java and ANT can read this in just fine, but bash can't:

[josh@earth temp]$ . test.properties
-bash: prop.two=this: command not found

Here are a few solutions that are a little more robust: http://shrubbery.mynetgear.net/c/display/W/Reading+Java-style+Properties+Files+with+Shell

[Tim Holloway]

Welcome to the CodeRanch, Joshua!

You're quite correct, and that page is a very useful resource.

It does, however, leave out 1 important method:

0. Don't use shell-hostile constructs in the shell-readable properties file!

When I use a properties file in the shell, I normally only put the coarsest properties in that file (which may include paths to finer-grade properties that the Java code itself reads). So it's no particular hardship to follow that rule. For me, anyway.

[Joshua Davis]

Fair enough, and thanks reading!

[Stefan Wagner]

cat prop.rc 
# this is a java properties file  
name=fred  
prop.two=this is property two  
age=42

Yes, this is quick and dirty:

for line in $(< prop.rc)
do
  case $line in
    name=*)  eval $line ;; # beware! eval!
    age=*)   eval $line ;; # dito!
    *) ;;
   esac
done
echo $name of $age 

> fred of 42

If age=$(rm -rf /), you loose, or name=Bobby$(psql pupil -c "DROP TABLE user").

[Miguel Angel Casanova]

Tim Holloway wrote:The easy way to do it is to note that a Java properties file has the same format as a basic shell script.

However, there's a trick to it. If you just run the properties file like so:

sh appl.properties

The assignments will be made at the sub-level, then discarded when the properties file (script) ends execution.

So to get the properties in a calling script, you need to use the "source" command:

. appl.properties

Note that the space after the initial dot is very important!

To reference shell variable assignments, you use the "$" to indicate variable substitution.

So, to put it all together:

#!/bin/sh
# Sample shell script to read and act on properties
 
# source the properties:
. appl.properties
 
# Then reference then:
echo "My name is $name and I'm $age years old."

Thank you!!!

[Campbell Ritchie]

Welcome to the Ranch MAC

[Jay Dilla]

[/code]

Here are a few solutions that are a little more robust: http://shrubbery.mynetgear.net/c/display/W/Reading+Java-style+Properties+Files+with+Shell



this is not working for me
what type of shell does this work with?

[Joshua Davis]

Jay Dilla wrote:
[/code]

Here are a few solutions that are a little more robust: http://shrubbery.mynetgear.net/c/display/W/Reading+Java-style+Properties+Files+with+Shell

this is not working for me
what type of shell does this work with?

It's bash. I've tested this on various Linux distros and Cygwin.

What, exactly is the problem you're having?

[Ivan Jozsef Balazs]

sameer sood wrote:This will require making properties file executable

No.

The . (source-in) operation dot does not need the file to be executable: readability suffices.

[Joe Maisel]

This is an old topic, but here's the solution I ended up using.


cat properties.file | sed 's/\./_/g' > .properties.file
. .properties.file
rm .properties.file

Use sed to replace "."s with "_"s, save as a new file, read it in, then delete it. You may not want or need to delete it based on your circumstance.

Now all the properties are available as environment variables with the "." chars replaced by "_" chars.