Let’s start with an example associative array: $ declare -A aa $ aa["foo"]=bar $ aa["a b"]=c. A few Bourne-like shells support associative arrays: ksh93 (since 1993), zsh (since 1998), bash (since 2009), though with some differences in behaviour between the 3. Elements in arrays are frequently referred to by their index number, which is the position in which they reside in the array. Bash & ksh: Bash associative arrays are supported in bash version 4. Bash: Associative array initialization and usage Just as in other programming languages, associative arrays in Bash are useful for search, set management, and keying into a list of values. You can assign values to arbitrary keys: $ Associative arrays (aka hashes) can be used since Bash v4 and need a declaration like this So far, you have used a limited number of variables in your bash script, you have created few variables to hold one or two filenames and usernames.. Bash & ksh: if [[ -v "MYARRAY[key5]" ]] ; then # code if key exist else # code if key does not exist fi Test if the value for a key is an empty string. They work quite similar as in python (and other languages, of course with fewer features :)). A common use is for counting occurrences of some strings. An associative array lets you create lists of key and value pairs, instead of just numbered values. Hashes in Bash. Bash, however, includes the ability to create associative arrays, and it treats these arrays the same as any other array. Before use associative array needs to be declared as shown below: declare -A hash hash=(["k1"]="v1" ["k2"]="v2") Copying associative arrays is not directly possible in bash. There are the associative arrays and integer-indexed arrays. See below for accessing the different properties of an array. There are at least 2 ways to get the keys from an associative array of Bash. The label may be different, but whether called “map”, “dictionary”, or “associative array… Declare and initialize associative array. Dictionary / associative arrays / hash map are very useful data structures and they can be created in bash. (by the way, bash hashes don't support empty keys). Arrays in Bash. Here is a quick start tutorial for using bash associative arrays. Bash & ksh: echo ${#MYARRAY[@]} Test if a key exist. Indexed arrays are accessed the same way as “Hashes”. For the record, in zsh, to turn two arrays into an associative array/hash, you'd do: typeset -A hash hash=("${(@)array1:^array2}") Where ${array1:^array2} is the array zipping operator and the @ parameter expansion flag is used to preserve empty elements (in double quotes, similar to "$@"). These index numbers are always integer numbers which start at 0. There is another solution which I used to pass variables to functions. The best solution probably is, as already been pointed out, to iterate through the array and copy it step by step. To iterate over the key/value pairs you can do something like the following example # For every… However, I find that things like: Arrays to the rescue! We will go over a few examples. In Bash, there are two types of arrays. To check the version of bash run following: Get the length of an associative array. You could use the same technique for copying associative arrays: But what if you need more than few variables in your bash scripts; let’s say you want to create a bash script that reads a hundred different input from a user, are you going to create 100 variables? dictionaries were added in bash version 4.0 and above. An associative array is an array which uses strings as indices instead of integers. The values of an associative array are accessed using the following syntax ${ARRAY[@]}. 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