CODEWITHSUNDEEP
shellproperties-file
Walking Corpse
Walking Corpse

Reputation: 83

Need bash shell script for reading name value pairs from a file

I have a file like

name1=value1
name2=value2

I need to read this file using shell script and set variables

$name1=value1
$name2=value2

Please provide a script that can do this.

I tried the first answer below, i.e. sourcing the properties file but I'm getting a problem if the value contains spaces. It gets interpreted as a new command after the space. How can I get it to work in the presence of spaces?

Upvotes: 35

Views: 68959

Answers (8)

Rajesh Kumar
Rajesh Kumar

Reputation: 11

    filename="config.properties"

# Read the file and extract key-value pairs
while IFS='=' read -r key value; do
    # Skip empty lines or lines starting with #
    if [[ -z $key || $key == \#* ]]; then
        continue
    fi

    # Trim leading/trailing whitespace from key
    key=$(echo "$key" | awk '{gsub(/^ +| +$/,"")} {print $0}')

    # Extract the value after the first equals sign
    value="${line#*=}"
    
    # Assign value to the variable dynamically
    declare "$key"="$value"
done < "$filename"

# Print the variables
echo "key1: $key1"
echo "key2: $key2"
echo "key3: $key3"

Upvotes: 1

Koichi Nakashima
Koichi Nakashima

Reputation: 959

Use shdotenv

dotenv support for shell and POSIX-compliant .env syntax specification https://github.com/ko1nksm/shdotenv

Usage: shdotenv [OPTION]... [--] [COMMAND [ARG]...]

  -d, --dialect DIALECT  Specify the .env dialect [default: posix]
                           (posix, ruby, node, python, php, go, rust, docker)
  -s, --shell SHELL      Output in the specified shell format [default: posix]
                           (posix, fish)
  -e, --env ENV_PATH     Location of the .env file [default: .env]
                           Multiple -e options are allowed
  -o, --overload         Overload predefined environment variables
  -n, --noexport         Do not export keys without export prefix
  -g, --grep PATTERN     Output only those that match the regexp pattern
  -k, --keyonly          Output only variable names
  -q, --quiet            Suppress all output
  -v, --version          Show the version and exit
  -h, --help             Show this message and exit

Load the .env file into your shell script.

eval "$(shdotenv [OPTION]...)"

Upvotes: 0

kurumi
kurumi

Reputation: 25609

Use:

while read -r line; do declare  "$line"; done <file

Upvotes: 23

Alex Stoliar
Alex Stoliar

Reputation: 335

if your file location is /location/to/file and the key is mykey:

grep mykey $"/location/to/file" | awk -F= '{print $2}'

Upvotes: 20

Daniel Alder
Daniel Alder

Reputation: 5382

Improved version of @robinst

read_properties()
{
  file="$1"
  while IFS="=" read -r key value; do
    case "$key" in
      '#'*) ;;
      *)
        eval "$key=\"$value\""
    esac
  done < "$file"
}

Changes:

  • Dynamic key mapping instead of static
  • Supports (skips) comment lines

A nice one is also the solution of @kurumi, but it isn't supported in busybox

And here a completely different variant:

eval "`sed -r -e "s/'/'\\"'\\"'/g" -e "s/^(.+)=(.+)\$/\1='\2'/" $filename`"

(i tried to do best with escaping, but I'm not sure if that's enough)

Upvotes: 7

robinst
robinst

Reputation: 31427

Sourcing the file using . or source has the problem that you can also put commands in there that are executed. If the input is not absolutely trusted, that's a problem (hello rm -rf /).

You can use read to read key value pairs like this if there's only a limited known amount of keys:

read_properties()
{
  file="$1"
  while IFS="=" read -r key value; do
    case "$key" in
      "name1") name1="$value" ;;
      "name2") name2="$value" ;;
    esac
  done < "$file"
}

Upvotes: 21

Clyde Lobo
Clyde Lobo

Reputation: 9174

suppose the name of your file is some.properties

#!/bin/sh
# Sample shell script to read and act on properties

# source the properties:
. some.properties

# Then reference then:
echo "name1 is $name1 and name2 is $name2"

Upvotes: 6

Joachim Sauer
Joachim Sauer

Reputation: 308141

If all lines in the input file are of this format, then simply sourcing it will set the variables:

source nameOfFileWithKeyValuePairs

or 

. nameOfFileWithKeyValuePairs

Upvotes: 38

Related Questions