|(operating system)||internal field separators - ($IFS) A predefined environment variable
in the Unix Bourne shell whose default value is the
three-character string containing space, tab and line feed. Any string of one or more of these characters
separates the command and each of its arguments in a command
$IFS also tells the shell's built-in read command where to split an input line when reading into multiple variables. E.g. setting IFS=: would be appropriate for reading a file with ':'-separated fields, such as /etc/passwd.