HACKTUX notes from the trenches

Arrays in Bash are quite simple. Here are some array examples to get you going. The official Bash documentation has more details and examples.

Initialize an entire array:

bash$ DAYS=(mon tue wed thu fri sat sun)

There are two ways to reference an entire array:

bash$ echo ${DAYS[@]}
mon tue wed thu fri sat sun
bash$ echo ${DAYS[*]}
mon tue wed thu fri sat sun

Initialize array element

bash$ ARRAY[0]="Fedora"
bash$ ARRAY[1]="RedHat"
bash$ ARRAY[2]="CentOS"

Display an element

bash$ echo ${ARRAY[0]}
Fedora

Get the length of an array:

bash$ echo ${#ARRAY[@]}
3

Get the length of an array value based on index:

bash$ echo ${ARRAY[0]}
Fedora
bash$ echo ${#ARRAY[0]}
6

Get the subset of an array through trailing substring extraction:

bash$ echo ${ARRAY[@]:0}
Fedora RedHat CentOS
bash$ echo ${ARRAY[@]:1}
RedHat CentOS
bash$ echo ${ARRAY[@]:2}
CentOS