#Format: s/search pattern/replacement string/g;
# Without the g option
while(){
print if s/Tom/Jack/; # First occurrence of Tom on each line is replaced with Jack
}
__DATA__
Tom Dave Dan Tom
Betty Tom Henry Tom
Jack Norma Tom Tom
# With the g option
while(){
print if s/Tom/Jack/g; # All occurrences of Tom on each line are replaced with Jack
}
__DATA__
Tom Dave Dan Tom
Betty Tom Henry Tom
Igor Norma Tom Tom