How do I grab an INI value within a shell script?

You can use bash native parser to interpret ini values, by:

$ source <(grep = file.ini)

Sample file:

[section-a]
  var1=value1
  var2=value2
  IPS=( "1.2.3.4" "1.2.3.5" )

To access variables, you simply printing them: echo $var1. You may also use arrays as shown above (echo ${IPS[@]}).

If you only want a single value just grep for it:

source <(grep var1 file.ini)

^{For the demo, check this recording at asciinema.}

It is simple as you don't need for any external library to parse the data, but it comes with some disadvantages. For example:

• If you have spaces between = (variable name and value), then you've to trim the spaces first, e.g.

    $ source <(grep = file.ini | sed 's/ *= */=/g')
  

  Or if you don't care about the spaces (including in the middle), use:

    $ source <(grep = file.ini | tr -d ' ')
  

• To support ; comments, replace them with #:

    $ sed "s/;/#/g" foo.ini | source /dev/stdin
  

• The sections aren't supported (e.g. if you've [section-name], then you've to filter it out as shown above, e.g. grep =), the same for other unexpected errors.

  If you need to read specific value under specific section, use grep -A, sed, awk or ex).

  E.g.

    source <(grep = <(grep -A5 '\[section-b\]' file.ini))
  

  ^{Note: Where -A5 is the number of rows to read in the section. Replace source with cat to debug.}

• If you've got any parsing errors, ignore them by adding: 2>/dev/null

See also:

• How to parse and convert ini file into bash array variables? at serverfault SE
• Are there any tools for modifying INI style files from shell script

Sed one-liner, that takes sections into account. Example file:

[section1]
param1=123
param2=345
param3=678

[section2]
param1=abc
param2=def
param3=ghi

[section3]
param1=000
param2=111
param3=222

Say you want param2 from section2. Run the following:

sed -nr "/^\[section2\]/ { :l /^param2[ ]*=/ { s/[^=]*=[ ]*//; p; q;}; n; b l;}" ./file.ini

will give you

def

How about grepping for that line then using awk

version=$(awk -F "=" '/database_version/ {print $2}' parameters.ini)