Is there a way to create key-value pairs in Bash script

Question

I am trying to create a dictionary of key value pair using Bash script  I am trying using this logic   declare -d dictionary defaults write   dictionary  key -string   value       where  dictionary is a variable  but this is not working   Is there a way to create key-value pairs in Bash script

User · Accepted Answer

In bash version 4 associative arrays were introduced.

declare -A arr

arr["key1"]=val1

arr+=( ["key2"]=val2 ["key3"]=val3 )

The arr array now contains the three key value pairs. Bash is fairly limited what you can do with them though, no sorting or popping etc.

for key in ${!arr[@]}; do
    echo ${key} ${arr[${key}]}
done

Will loop over all key values and echo them out.

Note: Bash 4 does not come with Mac OS X because of its GPLv3 license; you have to download and install it. For more on that see here

User · Answer

For persistent key value storage  you can use kv-bash  a pure bash implementation of key value database available at https   github com damphat kv-bash  Usage  git clone https   github com damphat kv-bash source kv-bash kv-bash   Try create some permanent variables  kvset myName  xyz kvset myEmail xyz example com   read the varible kvget myEmail   you can also use in another script with   kvget keyname  echo   kvget myEmail

User · Answer

In bash  we use declare -A name of dictonary variable  so that Bash understands it is a dictionary  For e g  you want to create sounds dictionary then  declare -A sounds  sounds dog   quot Bark quot   sounds wolf   quot Howl quot   where dog and wolf are  quot keys quot   and Bark and Howl are  quot values quot   You can access all values using   echo   sounds     OR echo   sounds     You can access all keys only using  echo    sounds     And if you want any value for a particular key  you can use    sounds dog   this will give you value  Bark  for key  Dog

User · Answer

If you can use a simple delimiter  a very simple oneliner is this   for i in a b c s d   do    KEY   i        VAL   i        echo  KEY  XX   VAL  done   Hereby i is filled with character sequences like  a b  and  c s d   each separated by spaces  After the do we use parameter substitution to extract the part before the comma   and the part after it

User · Answer

in older bash  or in sh  that does not support declare -A  following style can be used to emulate key value   key env staging     values image dev gcr io abc dev image staging gcr io abc stage image production gcr io abc stable  img var name image  env    active image    var name  active image   eval  quot echo    img var name quot    echo  active image

[bash] Is there a way to create key-value pairs in Bash script?

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