10-15-2012
Shell quoting rules for other languages programmers
I've seen so many times that programmers were confused about shell quoting and white spaces interpretation, that I decided to investigate that problem deeper. And my conclusion is that quoting in shells is
very different from other programming languages. Programmers who have bigger experience in C/Python/Java/PHP than in Shell should remember about two
unintuitive rules:
- everything in shell is a string, and one need to quote everything properly. Also when reading variables: "$X", not only storing X="hi there"
- shell will parse lines of code just one time, leaving unresolved nested variables and commands. In this case programmer need to explicitly use "eval" function.
I've written short article about this if anyone will be more curious you can find it under "white shell cofoh"
This User Gave Thanks to wyderkat For This Post:
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LEARN ABOUT DEBIAN
cpanplus::shell
CPANPLUS::Shell(3perl) Perl Programmers Reference Guide CPANPLUS::Shell(3perl)
NAME
CPANPLUS::Shell - base class for CPANPLUS shells
SYNOPSIS
use CPANPLUS::Shell; # load the shell indicated by your
# config -- defaults to
# CPANPLUS::Shell::Default
use CPANPLUS::Shell qw[Classic] # load CPANPLUS::Shell::Classic;
my $ui = CPANPLUS::Shell->new();
my $name = $ui->which; # Find out what shell you loaded
$ui->shell; # run the ui shell
DESCRIPTION
This module is the generic loading (and base class) for all "CPANPLUS" shells. Through this module you can load any installed "CPANPLUS"
shell.
Just about all the functionality is provided by the shell that you have loaded, and not by this class (which merely functions as a generic
loading class), so please consult the documentation of your shell of choice.
BUG REPORTS
Please report bugs or other issues to <bug-cpanplus@rt.cpan.org<gt>.
AUTHOR
This module by Jos Boumans <kane@cpan.org>.
COPYRIGHT
The CPAN++ interface (of which this module is a part of) is copyright (c) 2001 - 2007, Jos Boumans <kane@cpan.org>. All rights reserved.
This library is free software; you may redistribute and/or modify it under the same terms as Perl itself.
SEE ALSO
CPANPLUS::Shell::Default, CPANPLUS::Shell::Classic, cpanp
perl v5.14.2 2014-09-29 CPANPLUS::Shell(3perl)