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I have a variable that is entered at a prompt:

my $name = <>;

I want to append a fixed string '_one'to this (in a separate variable).

E.g. if $name = Smith then it becomes 'Smith_one'

I have tried several various ways which do not give me the right results, such as:

my $one = "${name}_one";

^ The _one appears on the next line when I print it out and when I use it, the _one is not included at all.

Also:

my $one = $name."_one";

^ The '_one' appears at the beginning of the string.

And: 

my $end = '_one';
my $one = $name.$end;
or 
my $one = "$name$end";

None of these produce the result I want, so I must be missing something related to how the input is formatted from the prompt, perhaps. Ideas appreciated!

dgBP
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1 Answers1

33

Your problem is unrelated to string appending: When you read a line (e.g. via <>), then the record input separator is included in that string; this is usually a newline \n. To remove the newline, chomp the variable:

    my $name = <STDIN>; # better use explicit filehandle unless you know what you are doing
    # now $name eq "Smith\n"
    chomp $name;
    # now $name eq "Smith"

To interpolate a variable into a string, you usually don't need the ${name} syntax you used. These lines will all append _one to your string and create a new string:

    "${name}_one"  # what you used
    "$name\_one"   # _ must be escaped, else the variable $name_one would be interpolated
    $name . "_one"
    sprintf "%s_one", $name
    # etc.

And this will append _one to your string and still store it in $name:

    $name .= "_one"
amon
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  • ahhh that is interesting about the newline character - chomp immediately solves the problem! I'd tried those methods of appending, too, with no luck - but now they all work! Thanks! – dgBP Sep 17 '12 at 12:52
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    Funny; I was thinking how much better to use `"${name}_one"` than awkward constructs like `"$name\_one"` or `$name . "_one"`. – Jonathan Leffler Mar 04 '17 at 06:52
  • @JonathanLeffler Thank you for your edit. By now, I'm also in the “`${foo}` is clear syntax, not an anachronistic bash-ism” camp, and that my original suggestions were worse. I've edited accordingly. – amon Mar 04 '17 at 10:51