linux bash tool to read property from property file

Question

I want to be able to run a command to get a property from a property file. So if my properties file is property.props and has

username=dsollen
password=letMeIn
linux-skills=newb

I would like to have a quick way to pull out the property to pipe into other commands. so

 ./myProgram -v -p `getProp property.props password`

or something like that; not sure I used the ` right, but that's a different newb linux question for later :)

I know I can do this with a combination of grep and cut/awk/sed/whatever, but I'm wondering if there is an already existing tool that 'knows' how to read common property file formats and does something like this? If not I could write something to add into my scripts folder, just don't want to reinvent the wheel if a better wheel already exists.

This might be relevant: http://wiki.bash-hackers.org/howto/conffile — Benjamin W., Apr 29 '16 at 16:12

Arturo Herrero · Accepted Answer · 2016-04-29T22:11:15.270

7

You can use gvar to do the work. I'm the author by the way.

From the source code, this is the interesting part for you:

get_variable() {
  < "$FILE" grep -w "$1" | cut -d'=' -f2
}

edited Apr 29 '16 at 22:11

answered Apr 29 '16 at 15:49

Arturo Herrero

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You may want to check your code with shellcheck.net. – chepner Apr 29 '16 at 15:52
my 5 second scan of the home page suggests this is for global variables only. can it be used to simply return a variable without making it global? – dsollen Apr 29 '16 at 16:19
@dsollen The function he posted doesn't make it a variable, it just returns the value. You can do whatever you want with the function. – Barmar Apr 29 '16 at 16:40

Alberto Zaccagni · Answer 2 · 2016-04-29T16:12:42.147

2

I assume your properties keys are unique, if so then the following might be a way:

grep -w "$1" <property.props

or to get the value

(grep -w "$1" | cut -d= -f2) <property.props

Where $1 is the key.

edited Apr 29 '16 at 16:12

answered Apr 29 '16 at 15:51

Alberto Zaccagni

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2

You should use `grep -w` otherwise you have a collision if you have `pass` and `password` in the file and you grep for `pass`. – Arturo Herrero Apr 29 '16 at 16:10
1

Ah that's a good TIL, thanks! :D – Alberto Zaccagni Apr 29 '16 at 16:12
This would be perfect if it worked for values split over multiple lines with `\\` – raffian Jun 14 '23 at 21:49

score 0 · Answer 3 · edited Apr 29 '16 at 20:38

0

Look, just define in your .bashrc a function:

getProp() {
  awk -F "=" "/^$2=/ {print "'$2'"; exit; }" $1
}

And use it in your shell:

$ getProp property.pros password
letMeIn

$ getProp property.pros linux-skills
newb

edited Apr 29 '16 at 20:38

John Kugelman

349,597
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answered Apr 29 '16 at 15:55

While this code may answer the question, providing additional context regarding why and/or how it answers the question would significantly improve its long-term value. Please [edit] your answer to add some explanation. – CodeMouse92 Apr 29 '16 at 19:09

linux bash tool to read property from property file

3 Answers3