open(IN, ">test");

print IN "In we go";

close(IN);

• > opens for output
• >> appends
• < opens for input
• | opens a pipe

$filename = $ARGV[0];       #get command line argument

open(IN, "<$filename");

$line = <IN>;               #read the first line
print $line;

while(<IN>) {               #loop as long as not EOF
print $_;                   #loop variable -- contains current line
}