Shell Programming and Scripting

# with a typed string
$ set -- a b c
$ echo $1
a
$ echo $2
b
$ echo $3
c

# with a variable
$ STR="abc def ghi"
$ set -- $STR
$ echo $1
abc
$ echo $2
def
$ echo $3
ghi

# What set, and variable expansion in general, splits on is controlled by the special
# IFS variable.  By default, IFS is any whitespace.  If you change it, remember to put it
# back when you're done.
$ OLDIFS="$IFS"
$ IFS="."
$ STR="W.Y.X"
$ set -- $STR
$ echo $1
W
$ echo $2
Y
$ echo $3
X

# But this does NOT work, because no variable gets expanded.
$ IFS="."
$ set -- X.Y.Z
$ echo $1
X.Y.Z
$ IFS="${OLDIFS}"