Create array in bash dynamically

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I would like to create and fill an array dynamically but it doesn't work like this:

while true; do
    read input
    echo {$field[$i]}  

The assignment is fine; the lookup is wrong:

echo "${field[$i]}"

Dynamically create array in bash with variables as array name , eval expects a string as the argument. You can't use ( unquoted, it has a special meaning in shell. i=aaa eval "$i=(1 2)" # Use a string, $i will expand in double� Define An Array in Bash You have two ways to create a new array in bash script. The first one is to use declare command to define an Array. This command will define an associative array named test_array.

Try something like this:

#! /bin/bash
while read -r input ; do
echo Num items: ${#field[@]}
echo Data: ${field[@]}

It stops reading when no more input is available (end of file, ^D in the keyboard), then prints the number of elements read and the whole array.

The Ultimate Bash Array Tutorial with 15 Examples, In bash, array is created automatically when a variable is used in the format / bin/bash $cat declare -a Unix=('Debian' 'Red hat'� Create indexed or associative arrays by using declare. Declare, in bash, it's used to set variables and attributes. In this case, since we provided the -a option, an indexed array has been created with the "my_array" name. This, as already said, it's the only way to create associative arrays in bash.

i= field=()
while :; do
    read -r 'field[i++]'

Is one way. mapfile is another. Or any of these. However what you've posted is valid.

Getting Bashed by Dynamic Arrays : Ludvik Jerabek, The script would use curl to make web-services calls, xmllint for XML parsing, and some other commonly used Linux tools such as grep. This� I'm trying to write a script in bash that will create an array that is the size of the number of arguments I give it. I'm expecting. user@host:~/sandbox# ./ alpha bravo charlie alpha bravo charlie or . user@host:~/sandbox# ./ 23425 jasson orange green verb noun coffee 23425 jasson orange green verb noun coffee So, the goal is

Assigning values for a dynamic array for an input, I am facing a strange error while creating posix threads: Given below are two snippets of code, the first one works whereas the second one gives a garbage value� So the while loop would be populating a copy of the results array, and when the while loop completes, that copy disappears. Edited to add: If that is the problem, then as glenn jackman points out in a comment, you can fix it by using process substitution instead:

set array name dynamically - UNIX and Linux Forums, Hi, I am trying to name a set of arrays dynamically named as @array_\\$i (The \\$i will mean that I obtain a set of arrays called: Tagged: array, bash, shell scripts, solved, strings, syntax, variables My idea is to do as follows I create array. Syntax is as follows. array= ( $ (command) ) By default the contents in the output of command separated by white spaces are plugged into array as individual elements. The following script list the contents of a directory, which are files with 755 permissions.

How to expand a loop iterating over an array dynamically in BASH , It doesn't work with a for in "${arr[@]}" loop because "${arr[@]}" is evaluated immediately. That is, even though you add elements to it during the loop, the� To initialize a Bash Array, use assignment operator =, and enclose all the elements inside braces (). The syntax to initialize a bash array is ARRAY_NAME= (ELEMENT_1 ELEMENT_2 ELEMENT _N) Note that there has to be no space around the assignment operator =.

  • What is your actual problem? Aside from some minor issues, your code is fine.
  • It works like a simple variable. If I the input is test, it echo: {test[0]}
  • I don't see any echo there. You just have an infinite loop that appends an array and does nothing with it. Yes expanding "$test" is always equivalent to "${test[0]}" (even if test isn't an array).
  • I edited the post. I added echo {$field[$i]}
  • I saw the error is the $ symbol after the bracket