1Sysadm::Install(3) User Contributed Perl Documentation Sysadm::Install(3)
2
6 Sysadm::Install - Typical installation tasks for system administrators
7
9 use Sysadm::Install qw(:all);
10 my $INST_DIR = '/home/me/install/';
12 cd($INST_DIR);
14 cp("/deliver/someproj.tgz", ".");
15 untar("someproj.tgz");
16 cd("someproj");
17 # Write out ...
19 blurt("Builder: Mike\nDate: Today\n", "build.dat");
20 # Slurp back in ...
22 my $data = slurp("build.dat");
23 # or edit in place ...
25 pie(sub { s/Today/scalar localtime()/ge; $_; }, "build.dat");
26 make("test install");
28 # run a cmd and tap into stdout and stderr
30 my($stdout, $stderr, $exit_code) = tap("ls", "-R");
31
33 Have you ever wished for your installation shell scripts to run
34 reproducibly, without much programming fuzz, and even with optional
35 logging enabled? Then give up shell programming, use Perl.
36 "Sysadm::Install" executes shell-like commands performing typical
38 installation tasks: Copying files, extracting tarballs, calling "make".
39 It has a "fail once and die" policy, meticulously checking the result
40 of every operation and calling die() immediately if anything fails.
41 "Sysadm::Install" also supports a dry_run mode, in which it logs
43 everything, but suppresses any write actions. Dry run mode is enabled
44 by calling Sysadm::Install::dry_run(1). To switch back to normal, call
45 Sysadm::Install::dry_run(0).
46 As of version 0.17, "Sysadm::Install" supports a confirm mode, in which
48 it interactively asks the user before running any of its functions
49 (just like "rm -i"). confirm mode is enabled by calling
50 Sysadm::Install::confirm(1). To switch back to normal, call
51 Sysadm::Install::confirm(0).
52 "Sysadm::Install" is fully Log4perl-enabled. To start logging, just
54 initialize "Log::Log4perl". "Sysadm::Install" acts as a wrapper class,
55 meaning that file names and line numbers are reported from the calling
56 program's point of view.
57 FUNCTIONS
59 "cp($source, $target)"
60 Copy a file from $source to $target. "target" can be a directory.
61 Note that "cp" doesn't copy file permissions. If you want the
62 target file to reflect the source file's user rights, use perm_cp()
63 shown below.
64 "mv($source, $target)"
66 Move a file from $source to $target. "target" can be a directory.
67 download($url)
69 Download a file specified by $url and store it under the name
70 returned by basename($url).
71 untar($tarball)
73 Untar the tarball in $tarball, which typically adheres to the
74 "someproject-X.XX.tgz" convention. But regardless of whether the
75 archive actually contains a top directory "someproject-X.XX", this
76 function will behave if it had one. If it doesn't have one, a new
77 directory is created before the unpacking takes place. Unpacks the
78 tarball into the current directory, no matter where the tarfile is
79 located. Please note that if you're using a compressed tarball
80 (.tar.gz or .tgz), you'll need IO::Zlib installed.
81 "untar_in($tar_file, $dir)"
83 Untar the tarball in $tgz_file in directory $dir. Create $dir if it
84 doesn't exist yet.
85 "pick($prompt, $options, $default, $opts)"
87 Ask the user to pick an item from a displayed list. $prompt is the
88 text displayed, $options is a referenc to an array of choices, and
89 $default is the number (starting from 1, not 0) of the default
90 item. For example,
91 pick("Pick a fruit", ["apple", "pear", "pineapple"], 3);
93 will display the following:
95 [1] apple
97 [2] pear
98 [3] pineapple
99 Pick a fruit [3]>
100 If the user just hits Enter, "pineapple" (the default value) will
102 be returned. Note that 3 marks the 3rd element of the list, and is
103 not an index value into the array.
104 If the user enters 1, 2 or 3, the corresponding text string
106 ("apple", "pear", "pineapple" will be returned by pick().
107 If the optional $opts hash has "{ tty => 1 }" set, then the user
109 response will be expected from the console, not STDIN.
110 "ask($prompt, $default, $opts)"
112 Ask the user to either hit Enter and select the displayed default
113 or to type in another string.
114 If the optional $opts hash has "{ tty => 1 }" set, then the user
116 response will be expected from the console, not STDIN.
117 mkd($dir)
119 Create a directory of arbitrary depth, just like
120 "File::Path::mkpath".
121 rmf($dir)
123 Delete a directory and all of its descendents, just like "rm -rf"
124 in the shell.
125 cd($dir)
127 chdir to the given directory. If you don't want to have cd() modify
128 the internal directory stack (used for subsequent cdback() calls),
129 set the stack_update parameter to a false value:
130 cd($dir, {stack_update => 0});
132 cdback()
134 chdir back to the last directory before a previous "cd". If the
135 option "reset" is set, it goes all the way back to the beginning of
136 the directory stack, i.e. no matter how many cd() calls were made
137 in between, it'll go back to the original directory:
138 # go all the way back
140 cdback( { reset => 1 } );
141 make()
143 Call "make" in the shell.
144 "pie($coderef, $filename, ...)"
146 Simulate "perl -pie 'do something' file". Edits files in-place.
147 Expects a reference to a subroutine as its first argument. It will
148 read out the file $filename line by line and calls the subroutine
149 setting a localized $_ to the current line. The return value of the
150 subroutine will replace the previous value of the line.
151 Example:
153 # Replace all 'foo's by 'bar' in test.dat
155 pie(sub { s/foo/bar/g; $_; }, "test.dat");
156 Works with one or more file names.
158 If the files are known to contain UTF-8 encoded data, and you want
160 it to be read/written as a Unicode strings, use the "utf8" option:
161 pie(sub { s/foo/bar/g; $_; }, "test.dat", { utf8 => 1 });
163 "plough($coderef, $filename, ...)"
165 Simulate "perl -ne 'do something' file". Iterates over all lines of
166 all input files and calls the subroutine provided as the first
167 argument.
168 Example:
170 # Print all lines containing 'foobar'
172 plough(sub { print if /foobar/ }, "test.dat");
173 Works with one or more file names.
175 If the files are known to contain UTF-8 encoded data, and you want
177 it to be read into Unicode strings, use the "utf8" option:
178 plough(sub { print if /foobar/ }, "test.dat", { utf8 => 1 });
180 "my $data = slurp($file, $options)"
182 Slurps in the file and returns a scalar with the file's content. If
183 called without argument, data is slurped from STDIN or from any
184 files provided on the command line (like <> operates).
185 If the file is known to contain UTF-8 encoded data and you want to
187 read it in as a Unicode string, use the "utf8" option:
188 my $unicode_string = slurp( $file, {utf8 => 1} );
190 "blurt($data, $file, $options)"
192 Opens a new file, prints the data in $data to it and closes the
193 file. If "$options->{append}" is set to a true value, data will be
194 appended to the file. Default is false, existing files will be
195 overwritten.
196 If the string is a Unicode string, use the "utf8" option:
198 blurt( $unicode_string, $file, {utf8 => 1} );
200 "blurt_atomic($data, $file, $options)"
202 Write the data in $data to a file $file, guaranteeing that the
203 operation will either complete fully or not at all. This is
204 accomplished by first writing to a temporary file which is then
205 rename()ed to the target file.
206 Unlike in "blurt", there is no $append mode in "blurt_atomic".
208 If the string is a Unicode string, use the "utf8" option:
210 blurt_atomic( $unicode_string, $file, {utf8 => 1} );
212 "($stdout, $stderr, $exit_code) = tap($cmd, @args)"
214 Run a command $cmd in the shell, and pass it @args as args.
215 Capture STDOUT and STDERR, and return them as strings. If
216 $exit_code is 0, the command succeeded. If it is different, the
217 command failed and $exit_code holds its exit code.
218 Please note that tap() is limited to single shell commands, it
220 won't work with output redirectors ("ls >/tmp/foo" 2>&1).
221 In default mode, tap() will concatenate the command and args given
223 and create a shell command line by redirecting STDERR to a
224 temporary file. "tap("ls", "/tmp")", for example, will result in
225 'ls' '/tmp' 2>/tmp/sometempfile |
227 Note that all commands are protected by single quotes to make sure
229 arguments containing spaces are processed as singles, and no
230 globbing happens on wildcards. Arguments containing single quotes
231 or backslashes are escaped properly.
232 If quoting is undesirable, tap() accepts an option hash as its
234 first parameter,
235 tap({no_quotes => 1}, "ls", "/tmp/*");
237 which will suppress any quoting:
239 ls /tmp/* 2>/tmp/sometempfile |
241 Or, if you prefer double quotes, use
243 tap({double_quotes => 1}, "ls", "/tmp/$VAR");
245 wrapping all args so that shell variables are interpolated
247 properly:
248 "ls" "/tmp/$VAR" 2>/tmp/sometempfile |
250 Another option is "utf8" which runs the command in a terminal set
252 to UTF8.
253 Error handling: By default, tap() won't raise an error if the
255 command's return code is nonzero, indicating an error reported by
256 the shell. If bailing out on errors is requested to avoid return
257 code checking by the script, use the raise_error option:
258 tap({raise_error => 1}, "ls", "doesn't exist");
260 In DEBUG mode, "tap" logs the entire stdout/stderr output, which
262 can get too verbose at times. To limit the number of bytes logged,
263 use the "stdout_limit" and "stderr_limit" options
264 tap({stdout_limit => 10}, "echo", "123456789101112");
266 "$quoted_string = qquote($string, [$metachars])"
268 Put a string in double quotes and escape all sensitive characters
269 so there's no unwanted interpolation. E.g., if you have something
270 like
271 print "foo!\n";
273 and want to put it into a double-quoted string, it will look like
275 "print \"foo!\\n\""
277 Sometimes, not only backslashes and double quotes need to be
279 escaped, but also the target environment's meta chars. A string
280 containing
281 print "$<\n";
283 needs to have the '$' escaped like
285 "print \"\$<\\n\";"
287 if you want to reuse it later in a shell context:
289 $ perl -le "print \"\$<\\n\";"
291 1212
292 qquote() supports escaping these extra characters with its second,
294 optional argument, consisting of a string listing all escapable
295 characters:
296 my $script = 'print "$< rocks!\\n";';
298 my $escaped = qquote($script, '!$'); # Escape for shell use
299 system("perl -e $escaped");
300 => 1212 rocks!
302 And there's a shortcut for shells: By specifying ':shell' as the
304 metacharacters string, qquote() will actually use '!$`'.
305 For example, if you wanted to run the perl code
307 print "foobar\n";
309 via
311 perl -e ...
313 on a box via ssh, you would use
315 use Sysadm::Install qw(qquote);
317 my $cmd = 'print "foobar!\n"';
319 $cmd = "perl -e " . qquote($cmd, ':shell');
320 $cmd = "ssh somehost " . qquote($cmd, ':shell');
321 print "$cmd\n";
323 system($cmd);
324 and get
326 ssh somehost "perl -e \"print \\\"foobar\\\!\\\\n\\\"\""
328 which runs on "somehost" without hickup and prints "foobar!".
330 Sysadm::Install comes with a script "one-liner" (installed in bin),
332 which takes arbitrary perl code on STDIN and transforms it into a
333 one-liner:
334 $ one-liner
336 Type perl code, terminate by CTRL-D
337 print "hello\n";
338 print "world\n";
339 ^D
340 perl -e "print \"hello\\n\"; print \"world\\n\"; "
341 "$quoted_string = quote($string, [$metachars])"
343 Similar to qquote(), just puts a string in single quotes and
344 escapes what needs to be escaped.
345 Note that shells typically don't support escaped single quotes
347 within single quotes, which means that
348 $ echo 'foo\'bar'
350 >
351 is invalid and the shell waits until it finds a closing quote.
353 Instead, there is an evil trick which gives the desired result:
354 $ echo 'foo'\''bar' # foo, single quote, \, 2 x single quote, bar
356 foo'bar
357 It uses the fact that shells interpret back-to-back strings as one.
359 The construct above consists of three back-to-back strings:
360 (1) 'foo'
362 (2) '
363 (3) 'bar'
364 which all get concatenated to a single
366 foo'bar
368 If you call quote() with $metachars set to ":shell", it will
370 perform that magic behind the scenes:
371 print quote("foo'bar");
373 # prints: 'foo'\''bar'
374 "perm_cp($src, $dst, ...)"
376 Read the $src file's user permissions and modify all $dst files to
377 reflect the same permissions.
378 "owner_cp($src, $dst, ...)"
380 Read the $src file/directory's owner uid and group gid and apply it
381 to $dst.
382 For example: copy uid/gid of the containing directory to a file
384 therein:
385 use File::Basename;
387 owner_cp( dirname($file), $file );
389 Usually requires root privileges, just like chown does.
391 "$perms = perm_get($filename)"
393 Read the $filename's user permissions and owner/group. Returns an
394 array ref to be used later when calling "perm_set($filename,
395 $perms)".
396 "perm_set($filename, $perms)"
398 Set file permissions and owner of $filename according to $perms,
399 which was previously acquired by calling perm_get($filename).
400 sysrun($cmd)
402 Run a shell command via system() and die() if it fails. Also works
403 with a list of arguments, which are then interpreted as program
404 name plus arguments, just like system() does it.
405 "hammer($cmd, $arg, ...)"
407 Run a command in the shell and simulate a user hammering the ENTER
408 key to accept defaults on prompts.
409 "say($text, ...)"
411 Alias for "print ..., "\n"", just like Perl6 is going to provide
412 it.
413 sudo_me()
415 Check if the current script is running as root. If yes, continue.
416 If not, restart the current script with all command line arguments
417 is restarted under sudo:
418 sudo scriptname args ...
420 Make sure to call this before any @ARGV-modifying functions like
422 getopts() have kicked in.
423 bin_find($program)
425 Search all directories in $PATH (the ENV variable) for an
426 executable named $program and return the full path of the first
427 hit. Returns "undef" if the program can't be found.
428 fs_read_open($dir)
430 Opens a file handle to read the output of the following process:
431 cd $dir; find ./ -xdev -print0 | cpio -o0 |
433 This can be used to capture a file system structure.
435 fs_write_open($dir)
437 Opens a file handle to write to a
438 | (cd $dir; cpio -i0)
440 process to restore a file system structure. To be used in
442 conjunction with fs_read_open.
443 "pipe_copy($in, $out, [$bufsize])"
445 Reads from $in and writes to $out, using sysread and syswrite. The
446 buffer size used defaults to 4096, but can be set explicitly.
447 "snip($data, $maxlen)"
449 Format the data string in $data so that it's only (roughly) $maxlen
450 characters long and only contains printable characters.
451 If $data is longer than $maxlen, it will be formatted like
453 (22)[abcdef[snip=11]stuvw]
455 indicating the length of the original string, the beginning, the
457 end, and the number of 'snipped' characters.
458 If $data is shorter than $maxlen, it will be returned unmodified
460 (except for unprintable characters replaced, see below).
461 If $data contains unprintable character's they are replaced by "."
463 (the dot).
464 "password_read($prompt, $opts)"
466 Reads in a password to be typed in by the user in noecho mode. A
467 call to password_read("password: ") results in
468 password: ***** (stars aren't actually displayed)
470 This function will switch the terminal back into normal mode after
472 the user hits the 'Return' key.
473 If the optional $opts hash has "{ tty => 1 }" set, then the prompt
475 will be redirected to the console instead of STDOUT.
476 nice_time($time)
478 Format the time in a human-readable way, less wasteful than the
479 'scalar localtime' formatting.
480 print nice_time(), "\n";
482 # 2007/04/01 10:51:24
483 It uses the system time by default, but it can also accept epoch
485 seconds:
486 print nice_time(1170000000), "\n";
488 # 2007/01/28 08:00:00
489 It uses localtime() under the hood, so the outcome of the above
491 will depend on your local time zone setting.
492 "def_or($foo, $default)"
494 Perl-5.9 added the //= construct, which helps assigning values to
495 undefined variables. Instead of writing
496 if(!defined $foo) {
498 $foo = $default;
499 }
500 you can just write
502 $foo //= $default;
504 However, this is not available on older perl versions (although
506 there's source filter solutions). Often, people use
507 $foo ||= $default;
509 instead which is wrong if $foo contains a value that evaluates as
511 false. So Sysadm::Install, the everything-and-the-kitchen-sink
512 under the CPAN modules, provides the function def_or() which can be
513 used like
514 def_or($foo, $default);
516 to accomplish the same as
518 $foo //= $default;
520 How does it work, how does $foo get a different value, although
522 it's apparently passed in by value? Modifying $_[0] within the
523 subroutine is an old Perl trick to do exactly that.
524 is_utf8_data($data)
526 Check if the given string has the utf8 flag turned on. Works just
527 like Encode.pm's is_utf8() function, except that it silently
528 returns a false if Encode isn't available, for example when an
529 ancient perl without proper utf8 support is used.
530 utf8_check($data)
532 Check if we're using a perl with proper utf8 support, by verifying
533 the Encode.pm module is available for loading.
534 home_dir()
536 Return the path to the home directory of the current user.
537
539 Mike Schilli, <m@perlmeister.com>
540
542 Copyright (C) 2004-2007 by Mike Schilli
543 This library is free software; you can redistribute it and/or modify it
545 under the same terms as Perl itself, either Perl version 5.8.3 or, at
546 your option, any later version of Perl 5 you may have available.
547perl v5.36.0 2023-01-20 Sysadm::Install(3)