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1 | package Shell; |
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2 | use 5.006_001; |
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3 | use strict; |
4 | use warnings; |
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5 | use File::Spec::Functions; |
6 | |
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7 | our($capture_stderr, $raw, $VERSION, $AUTOLOAD); |
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8 | |
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9 | $VERSION = '0.7'; |
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10 | |
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11 | sub new { bless \my $foo, shift } |
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12 | sub DESTROY { } |
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13 | |
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14 | sub import { |
15 | my $self = shift; |
16 | my ($callpack, $callfile, $callline) = caller; |
17 | my @EXPORT; |
18 | if (@_) { |
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19 | @EXPORT = @_; |
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20 | } else { |
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21 | @EXPORT = 'AUTOLOAD'; |
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22 | } |
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23 | foreach my $sym (@EXPORT) { |
24 | no strict 'refs'; |
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25 | *{"${callpack}::$sym"} = \&{"Shell::$sym"}; |
26 | } |
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27 | } |
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28 | |
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29 | # NOTE: this is used to enable constant folding in |
30 | # expressions like (OS eq 'MSWin32') and |
31 | # (OS eq 'os2') just like it happened in 0.6 version |
32 | # which used eval "string" to install subs on the fly. |
33 | use constant OS => $^O; |
34 | |
35 | =begin private |
36 | |
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37 | =over |
38 | |
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39 | =item B<_make_cmd> |
40 | |
41 | $sub = _make_cmd($cmd); |
42 | $sub = $shell->_make_cmd($cmd); |
43 | |
44 | Creates a closure which invokes the system command C<$cmd>. |
45 | |
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46 | =back |
47 | |
48 | =end private |
49 | |
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50 | =cut |
51 | |
52 | sub _make_cmd { |
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53 | shift if ref $_[0] && $_[0]->isa( 'Shell' ); |
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54 | my $cmd = shift; |
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55 | my $null = File::Spec::Functions::devnull(); |
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56 | $Shell::capture_stderr ||= 0; |
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57 | # closing over $^O, $cmd, and $null |
58 | return sub { |
59 | shift if ref $_[0] && $_[0]->isa( 'Shell' ); |
60 | if (@_ < 1) { |
61 | $Shell::capture_stderr == 1 ? `$cmd 2>&1` : |
62 | $Shell::capture_stderr == -1 ? `$cmd 2>$null` : |
63 | `$cmd`; |
64 | } elsif (OS eq 'os2') { |
65 | local(*SAVEOUT, *READ, *WRITE); |
66 | |
67 | open SAVEOUT, '>&STDOUT' or die; |
68 | pipe READ, WRITE or die; |
69 | open STDOUT, '>&WRITE' or die; |
70 | close WRITE; |
71 | |
72 | my $pid = system(1, $cmd, @_); |
73 | die "Can't execute $cmd: $!\n" if $pid < 0; |
74 | |
75 | open STDOUT, '>&SAVEOUT' or die; |
76 | close SAVEOUT; |
77 | |
78 | if (wantarray) { |
79 | my @ret = <READ>; |
80 | close READ; |
81 | waitpid $pid, 0; |
82 | @ret; |
83 | } else { |
84 | local($/) = undef; |
85 | my $ret = <READ>; |
86 | close READ; |
87 | waitpid $pid, 0; |
88 | $ret; |
89 | } |
90 | } else { |
91 | my $a; |
92 | my @arr = @_; |
93 | unless( $Shell::raw ){ |
94 | if (OS eq 'MSWin32') { |
95 | # XXX this special-casing should not be needed |
96 | # if we do quoting right on Windows. :-( |
97 | # |
98 | # First, escape all quotes. Cover the case where we |
99 | # want to pass along a quote preceded by a backslash |
100 | # (i.e., C<"param \""" end">). |
101 | # Ugly, yup? You know, windoze. |
102 | # Enclose in quotes only the parameters that need it: |
103 | # try this: c:> dir "/w" |
104 | # and this: c:> dir /w |
105 | for (@arr) { |
106 | s/"/\\"/g; |
107 | s/\\\\"/\\\\"""/g; |
108 | $_ = qq["$_"] if /\s/; |
109 | } |
110 | } else { |
111 | for (@arr) { |
112 | s/(['\\])/\\$1/g; |
113 | $_ = $_; |
114 | } |
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115 | } |
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116 | } |
117 | push @arr, '2>&1' if $Shell::capture_stderr == 1; |
118 | push @arr, '2>$null' if $Shell::capture_stderr == -1; |
119 | open(SUBPROC, join(' ', $cmd, @arr, '|')) |
120 | or die "Can't exec $cmd: $!\n"; |
121 | if (wantarray) { |
122 | my @ret = <SUBPROC>; |
123 | close SUBPROC; # XXX Oughta use a destructor. |
124 | @ret; |
125 | } else { |
126 | local($/) = undef; |
127 | my $ret = <SUBPROC>; |
128 | close SUBPROC; |
129 | $ret; |
130 | } |
131 | } |
132 | }; |
133 | } |
134 | |
135 | sub AUTOLOAD { |
136 | shift if ref $_[0] && $_[0]->isa( 'Shell' ); |
137 | my $cmd = $AUTOLOAD; |
138 | $cmd =~ s/^.*:://; |
139 | no strict 'refs'; |
140 | *$AUTOLOAD = _make_cmd($cmd); |
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141 | goto &$AUTOLOAD; |
142 | } |
143 | |
144 | 1; |
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145 | |
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146 | __END__ |
147 | |
148 | =head1 NAME |
149 | |
150 | Shell - run shell commands transparently within perl |
151 | |
152 | =head1 SYNOPSIS |
153 | |
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154 | use Shell qw(cat ps cp); |
155 | $passwd = cat('</etc/passwd'); |
156 | @pslines = ps('-ww'), |
157 | cp("/etc/passwd", "/tmp/passwd"); |
158 | |
159 | # object oriented |
160 | my $sh = Shell->new; |
161 | print $sh->ls('-l'); |
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162 | |
163 | =head1 DESCRIPTION |
164 | |
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165 | =head2 Caveats |
166 | |
167 | This package is included as a show case, illustrating a few Perl features. |
168 | It shouldn't be used for production programs. Although it does provide a |
169 | simple interface for obtaining the standard output of arbitrary commands, |
170 | there may be better ways of achieving what you need. |
171 | |
172 | Running shell commands while obtaining standard output can be done with the |
173 | C<qx/STRING/> operator, or by calling C<open> with a filename expression that |
174 | ends with C<|>, giving you the option to process one line at a time. |
175 | If you don't need to process standard output at all, you might use C<system> |
176 | (in preference of doing a print with the collected standard output). |
177 | |
178 | Since Shell.pm and all of the aforementioned techniques use your system's |
179 | shell to call some local command, none of them is portable across different |
180 | systems. Note, however, that there are several built in functions and |
181 | library packages providing portable implementations of functions operating |
182 | on files, such as: C<glob>, C<link> and C<unlink>, C<mkdir> and C<rmdir>, |
183 | C<rename>, C<File::Compare>, C<File::Copy>, C<File::Find> etc. |
184 | |
185 | Using Shell.pm while importing C<foo> creates a subroutine C<foo> in the |
186 | namespace of the importing package. Calling C<foo> with arguments C<arg1>, |
187 | C<arg2>,... results in a shell command C<foo arg1 arg2...>, where the |
188 | function name and the arguments are joined with a blank. (See the subsection |
189 | on Escaping magic characters.) Since the result is essentially a command |
190 | line to be passed to the shell, your notion of arguments to the Perl |
191 | function is not necessarily identical to what the shell treats as a |
192 | command line token, to be passed as an individual argument to the program. |
193 | Furthermore, note that this implies that C<foo> is callable by file name |
194 | only, which frequently depends on the setting of the program's environment. |
195 | |
196 | Creating a Shell object gives you the opportunity to call any command |
197 | in the usual OO notation without requiring you to announce it in the |
198 | C<use Shell> statement. Don't assume any additional semantics being |
199 | associated with a Shell object: in no way is it similar to a shell |
200 | process with its environment or current working directory or any |
201 | other setting. |
202 | |
203 | =head2 Escaping Magic Characters |
204 | |
205 | It is, in general, impossible to take care of quoting the shell's |
206 | magic characters. For some obscure reason, however, Shell.pm quotes |
207 | apostrophes (C<'>) and backslashes (C<\>) on UNIX, and spaces and |
208 | quotes (C<">) on Windows. |
209 | |
210 | =head2 Configuration |
211 | |
212 | If you set $Shell::capture_stderr to true, the module will attempt to |
213 | capture the standard error output of the process as well. This is |
214 | done by adding C<2E<gt>&1> to the command line, so don't try this on |
215 | a system not supporting this redirection. |
216 | |
217 | If you set $Shell::raw to true no quoting whatsoever is done. |
218 | |
219 | =head1 BUGS |
220 | |
221 | Quoting should be off by default. |
222 | |
223 | It isn't possible to call shell built in commands, but it can be |
224 | done by using a workaround, e.g. shell( '-c', 'set' ). |
225 | |
226 | Capturing standard error does not work on some systems (e.g. VMS). |
227 | |
228 | =head1 AUTHOR |
229 | |
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230 | Date: Thu, 22 Sep 94 16:18:16 -0700 |
231 | Message-Id: <9409222318.AA17072@scalpel.netlabs.com> |
232 | To: perl5-porters@isu.edu |
233 | From: Larry Wall <lwall@scalpel.netlabs.com> |
234 | Subject: a new module I just wrote |
235 | |
236 | Here's one that'll whack your mind a little out. |
237 | |
238 | #!/usr/bin/perl |
239 | |
240 | use Shell; |
241 | |
242 | $foo = echo("howdy", "<funny>", "world"); |
243 | print $foo; |
244 | |
245 | $passwd = cat("</etc/passwd"); |
246 | print $passwd; |
247 | |
248 | sub ps; |
249 | print ps -ww; |
250 | |
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251 | cp("/etc/passwd", "/etc/passwd.orig"); |
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252 | |
253 | That's maybe too gonzo. It actually exports an AUTOLOAD to the current |
254 | package (and uncovered a bug in Beta 3, by the way). Maybe the usual |
255 | usage should be |
256 | |
257 | use Shell qw(echo cat ps cp); |
258 | |
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259 | Larry Wall |
260 | |
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261 | Changes by Jenda@Krynicky.cz and Dave Cottle <d.cottle@csc.canterbury.ac.nz>. |
262 | |
263 | Changes for OO syntax and bug fixes by Casey West <casey@geeknest.com>. |
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264 | |
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265 | C<$Shell::raw> and pod rewrite by Wolfgang Laun. |
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266 | |
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267 | Rewritten to use closures rather than C<eval "string"> by Adriano Ferreira. |
268 | |
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269 | =cut |