IFS Internal Field Separator — GNU Bash.

$ 4.2.36 1 501---> echo $*

$ 4.2.36 2 502---> echo "$*"

$ 4.2.36 3 503---> echo $IFS

$ 4.2.36 4 504---> set $IFS=rightleftwrong
$ 4.2.36 5 505---> echo $*
=rightleftwrong
$ 4.2.36 6 506---> echo "$*"
=rightleftwrong
$ 4.2.36 7 507---> echo $IFS

$ 4.2.36 8 508---> echo $*
=rightleftwrong
$ 4.2.36 9 509---> read $*
jeff
bash: read: `=rightleftwrong': not a valid identifier
$ 4.2.36 10 510---> read $*
bash: read: `=rightleftwrong': not a valid identifier
$ 4.2.36 11 511---> read $*;
bash: read: `=rightleftwrong': not a valid identifier
$ 4.2.36 12 512--->  var1=1+2+3
$ 4.2.36 13 513---> echo $var1
1+2+3
$ 4.2.36 14 514---> IFS=+
$ 4.2.36 15 515---> echo $var1
1 2 3
$ 4.2.36 16 516---> IFS=-
$ 4.2.36 17 517---> echo $var1
1+2+3
$ 4.2.36 18 518---> IFS=" "
$ 4.2.36 19 519---> echo $var1
1+2+3
$ 4.2.36 20 520---> IFS=","
$ 4.2.36 21 521---> echo $var1
1+2+3
$ 4.2.36 22 522--->  var1=1+2,+3
$ 4.2.36 23 523---> echo $var1
1+2 +3
$ 4.2.36 24 524--->