Shell Programming and Scripting

read foo

echo $foo | ./myperlscript.pl

while (<STDIN>) {
print $_;
...
}

./myperlscript.pl $foo

print $ARGV[0];

...
${parameter^pattern}
${parameter^^pattern}
${parameter,pattern}
${parameter,,pattern}
    Case  modification.   This  expansion modifies the case of alphabetic characters in parameter.  The pattern is expanded to
    produce a pattern just as in pathname expansion.  The ^ operator converts lowercase letters matching pattern to uppercase;
    the  , operator converts matching uppercase letters to lowercase.  The ^^ and ,, expansions convert each matched character
    in the expanded value; the ^ and , expansions match and convert only the first character in the expanded value..  If  pat‐
    tern  is  omitted,  it  is treated like a ?, which matches every character.  If parameter is @ or *, the case modification
    operation is applied to each positional parameter in turn, and the expansion is the resultant list.  If  parameter  is  an
    array  variable  subscripted  with @ or *, the case modification operation is applied to each member of the array in turn,
    and the expansion is the resultant list.
...

$ typeset -u bla=Hallo
$ echo $bla
HALLO
$ typeset -l bla=Hallo
$ echo $bla
hallo