mapfile

mapfile also called (read array) is a command of the Bash shell used to read arrays. It reads lines from the standard input into an array variable. Also, mapfile must read from substitution (< <) and not from a pipe. 

Only available from bash 4.

Also, mapfile is faster and more convenient when compared to a read loop. It returns 1 or 0 depending on whether the command was successful or not. If no array name is not specified, the default variable MAPFILE is used as the target array variable.

Syntax: mapfile [array]

Alternatively, we can use read array [arrayname] instead of mapfile.

Example 1. Reading an array from a file:

$ mapfile MYFILE < example.txt

$ echo ${MYFILE[@]}

$ echo ${MYFILE[0]}

Example 2. Capture the output into an array:

$ mapfile TESTARRAY < <(printf "Item 1\nItem 2\nItem 3\n")

$ echo  ${TESTARRAY[@]}

Here, Item1, Item2, and Item 3 have been stored in the array TESTARRAY.

Example 3. Strip newlines and store item using -t:

$ mapfile -t TESTARRAY< <(printf "Item 1\nItem 2\nItem 3\n")

$ printf "%s\n" "${TESTARRAY[@]}"

$ mapfile -n 2 TESTARRAY < example.txt

$ echo  ${TESTARRAY[@]}