Convert multiline string to array

Question

I have this script:

nmapout=`sudo nmap -sP 10.0.0.0/24` names=`echo "$nmapout" | grep "MAC" | grep -o '(.\+)'` echo "$names" 

now the $names variable contains strings delimited with newlines:

>_  (Netgear)  (Hon Hai Precision Ind. Co.)  (Apple) 

I tried to do the array conversion with the sub-string approach:

names=(${names//\\n/ }) echo "${names[@]}" 

But the problem is that I can't access them by indexing (i.e., ${names[$i] etc.), if I run this loop

for (( i=0; i<${#names[@]}; i++ )) do      echo "$i: ${names[$i]"      # do some processing with ${names[$i]} done 

I get this output:

>_  0: (Netgear)  1: (Hon  2: Hai 

but what I want is:

>_  0: (Netgear)  1: (Hon Hai Precision Ind. Co.)  2: (Apple) 

I could not figure out a good way to do this, please note that the second string has spaces in it.

Answer 1

Set IFS (Internal Field Separator). Shell uses the IFS variable to determine what the field separators are. By default, IFS is set to the space character. Change it to the newline character, as demonstrated below:

#!/bin/bash names="Netgear Hon Hai Precision Ind. Co. Apple"      SAVEIFS=$IFS   # Save current IFS (Internal Field Separator) IFS=$'\n'      # Change IFS to newline char names=($names) # split the `names` string into an array by the same name IFS=$SAVEIFS   # Restore original IFS  for (( i=0; i<${#names[@]}; i++ )) do     echo "$i: ${names[$i]}" done 

Output

0: Netgear 1: Hon Hai Precision Ind. Co. 2: Apple 

Answer 2

Bash also has a readarray builtin command, easily searchable in the man page. It uses newline (\n) as the default delimiter, and MAPFILE as the default array, so one can do just like so:

    names="Netgear     Hon Hai Precision Ind. Co.     Apple"      readarray -t <<<$names      printf "0: ${MAPFILE[0]}\n1: ${MAPFILE[1]}\n2: ${MAPFILE[2]}\n" 

The -t option removes the delimiter ('\n'), so that it can be explicitly added in printf. The output is:

    0: Netgear     1: Hon Hai Precision Ind. Co.     2: Apple