As a preface, I spent 3 years engineering and implementing a pretty complicated command line toolset in Perl for a major financial company. The ideas below are basically part of our team’s design guidelines. User Interface Command line option: allow as many as possible have default values. NO positional parameters for any command that has … Read more
opendir(D, “/path/to/directory”) || die “Can’t open directory: $!\n”; while (my $f = readdir(D)) { print “\$f = $f\n”; } closedir(D); EDIT: Oh, sorry, missed the “into an array” part: my $d = shift; opendir(D, “$d”) || die “Can’t open directory $d: $!\n”; my @list = readdir(D); closedir(D); foreach my $f (@list) { print “\$f = … Read more
Pass the reference instead of the hash itself. As in PrintAA(“abc”, \%fooHash); sub PrintAA { my $test = shift; my $aaRef = shift; print $test, “\n”; foreach (keys %{$aaRef}) { print $_, ” : “, $aaRef->{$_}, “\n”; } } See also perlfaq7: How can I pass/return a {Function, FileHandle, Array, Hash, Method, Regex}?
If you installed the mysql server that everybody installs: sudo apt-get install mysql-server (or something like this) you are missing a few extra files on which the makefile for this perl module depends. You can try to work around this issue by installing the following package: sudo apt-get install libmysqlclient-dev REFERECE: http://cpansearch.perl.org/src/RUDY/DBD-mysql-2.9008/INSTALL.html#configuration
^M is carriage return. You can do this: $str =~ s/\r//g
Without quotes is better. It’s in {} so it’s obvious that you are not using barewords, plus it is both easier to read and type (two less symbols). But all of this depends on the programmer, of course.
The parent shell, where you entered ./myscript.sh, first tried to execve it, which is where the shebang line would take effect if present. When this works, the parent is unaware of the difference between scripts and ELFs because the kernel takes care of it. The execve failed, so an ancient unix compatibility feature, predating the … Read more
perl -d your_script.pl args is how you debug Perl. It launches you into an interactive gdb-style command line debugger.
rindex $string, $substring, 0 searches for $substring in $string at position <=0 which is only possible if $substring is a prefix of $string. Example: > rindex “abc”, “a”, 0 0 > rindex “abc”, “b”, 0 -1
Use ${foo}: print <<EOF; ${foo}AAAAAAAA${foo}BBBBBBBB”; EOF