NAME

Sysadm::Install - Typical installation tasks for system administrators

SYNOPSIS

use Sysadm::Install qw(:all);

my $INST_DIR = '/home/me/install/';

cd($INST_DIR);
cp("/deliver/someproj.tgz", ".");
untar("someproj.tgz");
cd("someproj");

   # Write out ...
blurt("Builder: Mike\nDate: Today\n", "build.dat");

   # Slurp back in ...
my $data = slurp("build.dat");

   # or edit in place ...
pie(sub { s/Today/scalar localtime()/ge; $_; }, "build.dat");

make("test install");

   # run a cmd and tap into stdout and stderr
my($stdout, $stderr) = tap("ls -R");

DESCRIPTION

Have you ever wished for your installation shell scripts to run reproducably, without much programming fuzz, and even with optional logging enabled? Then give up shell programming, use Perl.

Sysadm::Install executes shell-like commands performing typical installation tasks: Copying files, extracting tarballs, calling make. It has a fail once and die policy, meticulously checking the result of every operation and calling die() immeditatly if anything fails.

FUNCTIONS

cp($source, $target)

Copy a file from $source to $target. target can be a directory. Note that cp doesn't copy file permissions. If you want the target file to reflect the source file's user rights, use perm_cp() shown below.

mv($source, $target)

Move a file from $source to $target. target can be a directory.

download($url)

Download a file specified by $url and store it under the name returned by basename($url).

untar($tgz_file)

Untar the tarball in $tgz_file, which typically adheres to the someproject-X.XX.tgz convention. But regardless of whether the archive actually contains a top directory someproject-X.XX, this function will behave if it had one. If it doesn't have one, a new directory is created before the unpacking takes place. Unpacks the tarball into the current directory, no matter where the tarfile is located.

untar_in($tar_file, $dir)

Untar the tarball in $tgz_file in directory $dir. Create $dir if it doesn't exist yet.

pick($prompt, $options, $default)

Ask the user to pick an item from a displayed list. $prompt is the text displayed, $options is a referenc to an array of choices, and $default is the number (starting from 1, not 0) of the default item. For example,

pick("Pick a fruit", ["apple", "pear", "pineapple"], 3);

will display the following:

[1] apple
[2] pear
[3] pineapple
Pick a fruit [3]>

If the user just hits Enter, "pineapple" (the default value) will be returned. Note that 3 marks the 3rd element of the list, and is not an index value into the array.

If the user enters 1, 2 or 3, the corresponding text string ("apple", "pear", "pineapple" will be returned by pick().

ask($prompt, $default)

Ask the user to either hit Enter and select the displayed default or to type in another string.

mkd($dir)

Create a directory of arbitrary depth, just like File::Path::mkpath.

rmf($dir)

Delete a directory and all of its descendents, just like rm -rf in the shell.

cd($dir)

chdir to the given directory.

cdback()

chdir back to the last directory before a previous cd.

make()

Call make in the shell.

pie($coderef, $filename, ...)

Simulate "perl -pie 'do something' file". Edits files in-place. Expects a reference to a subroutine as its first argument. It will read out the file $filename line by line and calls the subroutine setting a localized $_ to the current line. The return value of the subroutine will replace the previous value of the line.

Example:

# Replace all 'foo's by 'bar' in test.dat
    pie(sub { s/foo/bar/g; $_; }, "test.dat");

Works with one or more file names.

plough($coderef, $filename, ...)

Simulate "perl -ne 'do something' file". Iterates over all lines of all input files and calls the subroutine provided as the first argument.

Example:

# Print all lines containing 'foobar'
    plough(sub { print if /foobar/ }, "test.dat");

Works with one or more file names.

my $data = slurp($file)

Slurps in the file and returns a scalar with the file's content.

blurt($data, $file, $append)

Opens a new file, prints the data in $data to it and closes the file. If $append is set to a true value, data will be appended to the file. Default is false, existing files will be overwritten.

($stdout, $stderr) = tap($cmd)

Run a command $cmd in the shell, capture STDOUT and STDERR, and return them as strings.

$quoted_string = qquote($string, [$metachars])

Put a string in double quotes and escape all sensitive characters so there's no unwanted interpolation. E.g., if you have something like

print "foo!\n";

and want to put it into a double-quoted string, it will look like

"print \"foo!\\n\""

Sometimes, not only backslashes and double quotes need to be escaped, but also the target environment's meta chars. A string containing

print "$<\n";

needs to have the '$' escaped like

"print \"\$<\\n\";"

if you want to reuse it later in a shell context:

$ perl -le "print \"\$<\\n\";"
1212

qquote() supports escaping these extra characters with its second, optional argument, consisting of a string listing all escapable characters:

my $script  = 'print "$< rocks!\\n";';
my $escaped = qquote($script, '!$'); # Escape for shell use
system("perl -e $escaped");

=> 1212 rocks!

And there's a shortcut for shells: By specifying ':shell' as the metacharacters string, qquote() will actually use '!$`'.

For example, if you wanted to run the perl code

print "foobar\n";

via

perl -e ...

on a box via ssh, you would use

use Sysadm::Install qw(qquote);

my $cmd = 'print "foobar!\n"';
   $cmd = "perl -e " . qquote($cmd, ':shell');
   $cmd = "ssh somehost " . qquote($cmd, ':shell');

print "$cmd\n";
system($cmd);

and get

ssh somehost "perl -e \"print \\\"foobar\\\!\\\\n\\\"\""

which runs on somehost without hickup and prints foobar!.

perm_cp($src, $dst, ...)

Read the $src file's user permissions and modify all $dst files to reflect the same permissions.

sysrun($cmd)

Run a shell command via system() and die() if it fails.

hammer($cmd, $arg, ...)

Run a command in the shell and simulate a user hammering the ENTER key to accept defaults on prompts.

AUTHOR

Mike Schilli, <m@perlmeister.com>

COPYRIGHT AND LICENSE

Copyright (C) 2004 by Mike Schilli

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.3 or, at your option, any later version of Perl 5 you may have available.