Overview - Chapter: 0:History, 1:Design, 2:Basics, 3:Var, 4:Op, 5:IO, 6:{}, 7:Sub, 8:OOP, 9:Rx, 10:Meta
Intro - Appendices: A:Index, B:Tables, C:Cook, D:Delta, E:Best of, F:Links
Herbert Breunung: Inside a shell might be a Perl.
This tablet is about the old core business of Perl.
Command Line
The shell, command line (or STDOUT to Perl 5 programmer and $*OUT in Perl 6) is the first and most fundamental communication device for a script with it's user. And most tutorials begin just with putting a line to that black window.
say
say "dear earthlings";
This just drops a quoted string but any other kind of value is possible. say will just append an invisible newline character, according to you operating system. So every time you "say" something, it will start on a fresh line.
You can also give say a list of values. Each item will be taken as an expression, that has to evaluated. The results will be combined, just like with ~ and the \n will be added on the end.
say "dear earthlings, we come from ", $our_home_planet, ",that is ", compute_distance($earth, $our_home_planet), 'parsecs away.';
.. does pretty much the same as say, just without the "\n". Maybe you can memorize it with the following thought: Machines to print, character by character without stop and hidden meaning. People on the other hand speak in sentences or speech balloons, which have to be seperated.
printf
It's a print that understands also the syntax of sprintf. Its you lightweight framework for formated output. If you need more, use formats.
note
Works like say and writes also on the command line, but via the $*ERR handler, formally known as STDERR which can be redirected to other programs who want just listen to you error messages.
warn
The print version that writes to to $*ERR.
prompt
That allows a 2 way communication with the commandline. It does an output like say and waits then for intput, until the user hits the enter key. It returns everything typed, except the trailing enter per default. So unlike Perl 5 you normally don't have to chomp any input from the command line. All following commands behave that way.
$location = prompt "Where is the next service station, we have almost no anti matter left?";
read
$*CWD
Files
slurp
lines
open
readline
get
getc
read for files
print for files
say for files
open
Synopsis:
open('new', :w).close
given open('foo', :w) { # "Anonymous" filehandle.say('Hello, world!');}
.close
Valid modes are:
r : read
w : write
a : append (Note: you must specify "wa", not just "a")
p : pipe
close
rename for files
Directories
dir
mkdir
chdir
chroot
rmdir
rename
Sockets
Processes
run
runinstead
fork
wait
kill
Overview - Chapter: 0:History, 1:Design, 2:Basics, 3:Var, 4:Op, 5:IO, 6:{}, 7:Sub, 8:OOP, 9:Rx, 10:Meta
Intro - Appendices: A:Index, B:Tables, C:Cook, D:Delta, E:Best of, F:Links
