Bash array arent adding elements to last

Question

root@kali-linux:~/Softwares/Softwares/Tools/dirsearch# array=() root@kali-linux:~/Softwares/Softwares/Tools/dirsearch# for i in 1 2 3 4 > do > array+=($i) > done root@kali-linux:~/Softwares/Softwares/Tools/dirsearch# echo $array 1 root@kali-linux:~/Softwares/Softwares/Tools/dirsearch# for i in 1 2 3 4; do array+=( $i ); done root@kali-linux:~/Softwares/Softwares/Tools/dirsearch# echo $array 1 root@kali-linux:~/Softwares/Softwares/Tools/dirsearch# for i in 1 2 3 4; do array+=( $i ); done root@kali-linux:~/Softwares/Softwares/Tools/dirsearch# for i in 1 2 3 4; do > array=( "${array[@]}" "$i" ) > done root@kali-linux:~/Softwares/Softwares/Tools/dirsearch# echo $array 1 root@kali-linux:~/Softwares/Softwares/Tools/dirsearch# 

How to add/remove an element to/from the array in bash? I tried to add like as said in this question still it doesnt work and print 1

Answer 1

Your loop is fine (except that you forgot to quote $i), the problem is in your echo $array, which doesn't print all the elements of the array in bash.

bash has copied the awkward array design of ksh instead of that of zsh, csh, tcsh, rc...

In ksh, $array is short for ${array[0]} (expands to the contents of the element of indice 0 or an empty string if it's not set).

To expand to all the elements of the array, you need:

$ printf ' - "%s"\n' "${array[@]}" - "1" - "2" - "3" - "4" 

For the first element of the array (which may not be the one with indice 0 as ksh/bash arrays are sparse):

$ printf '%s\n' "${array[@]:0:1}" 1 

And for the element of indice 0 (which in your example is going to be the same as the first element):

$ printf '%s\n' "$array" 1 

or:

$ printf '%s\n' "${array[0]}" 1 

To print the definition of a variable, you can also use typeset -p:

ksh93u+$ typeset -p array typeset -a array=( 1 2 3 4 ) 

bash-5.0$ typeset -p array declare -a array=([0]="1" [1]="2" [2]="3" [3]="4") bash-5.0$ unset 'array[0]' bash-5.0$ typeset -p array declare -a array=([1]="2" [2]="3" [3]="4") bash-5.0$ printf '%s\n' "$array" bash-5.0$ printf '%s\n' "${array[@]:0:1}" 2