Ystem> ($IFS) A predefined environment variable in the UnixBourne 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 line. $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. (1999-04-07)