perltutorial root In perl there are two ways to represent string literals: single-quoted strings and double-quoted strings.<BR> <BR><B>Single-Quoted Strings</B><BR><BR> Single quoted are a sequence of characters that begin and end with a single quote. These quotes are not a part of the string they just mark the beginning and end for the Perl interpreter. If you want a ' inside of your string you need to preclude it with a \ like this \' as you'll see below. Let's see how this works below.<BR> <PRE> 'four' #has four letters in the string 'can\'t' #has five characters and represents "can't" 'hi\there' #has eight characters and represents"hi\\there" (one \ in the string) 'blah\\blah' #has nine characters and represents "blah\\blah" (one \ in the string) </PRE> If you want to put a new line in a single-quoted string it goes something like this<BR> <PRE> 'line1 line2' #has eleven characters line1, newline character, and then line2 </PRE> Single-quoted strings don't interpret \n as a newline. <BR><BR> <B>Double-Quoted Strings</B><BR> Double quoted strings act more like strings in C or C++ the backslash allows you to represent control characters. Another nice feature Double-Quoted strings offers is variable interpolation this substitutes the value of a variable into the string. Some examples are below<BR> <PRE> $word="hello"; #$word becomes hello $statement="$word world"; #variable interpolation, $statement becomes "hello world" "Hello World\n"; #"Hello World" followed by a newline </PRE> <BR> <B>Some of the things you can put in a Double-Quoted String</B><BR> <TABLE BORDER=1> <TR><TD>Representation</TD><TD>What it Means</TD></TR> <TR><TD>\a</TD><TD>Bell</TD></TR> <TR><TD>\b</TD><TD>Backspace</TD></TR> <TR><TD>\e</TD><TD>Escape</TD></TR> <TR><TD>\f</TD><TD>Formfeed</TD></TR> <TR><TD>\n</TD><TD>Newline</TD></TR> <TR><TD>\r</TD><TD>Return</TD></TR> <TR><TD>\t</TD><TD>Tab</TD></TR> <TR><TD>\\</TD><TD>Backslash</TD></TR> <TR><TD>\"</TD><TD>Double quote</TD></TR> <TR><TD>\007</TD><TD>octal ascii value this time 007 or the bell</TD></TR> <TR><TD>\x07</TD><TD>hex ascii value this time 007 or the bell</TD></TR> <TR><TD>\cD</TD><TD>any control character.. here it is control-D</TD></TR> <TR><TD>\l</TD><TD>lowercase next letter</TD></TR> <TR><TD>\u</TD><TD>uppercase next letter</TD></TR> <TR><TD>\L</TD><TD>lowercase all letters until \E</TD></TR> <TR><TD>\U</TD><TD>uppercase all letters until \E</TD></TR> <TR><TD>\Q</TD><TD>Backslash quote all nonletters and nonnumbers until \E</TD></TR> <TR><TD>\E</TD><TD>Stop \U \L or \Q</TD></TR> </TABLE>