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Full Discussion: Perl syntax
Top Forums Shell Programming and Scripting Perl syntax Post 302809111 by DGPickett on Saturday 18th of May 2013 09:12:13 AM
Old 05-18-2013
First, I know almost no perl, but that never stops me!

-> is stolen from C, says point to a child member of, in this case a member function or method of a class/object/struct type.

=> is somewhat synonymous with a comma, and has functions by context as a list separator or left operand discard, like in c you can say "x = ( y == 3 ? printf("Equal\n"), 1 : 0 );", which is assign to x the result of test y equal 3 if true printf and then discard the printf return and supply a 1 else supply a 0, which is an ugly way to say if y is three than printf and set x to 1 else set x to 0. The comma discards the return of the printf, and connects two commands that run together like a {}, especially handyin contexts where {} are not legal. However, the comma has special meanings by context, like separating key from value in a hash table. (A hash table is a lookup by some integer derived (hashed) from the key, to pick one of N buckets where there may be multiple but few key value pairs that have to be searched linearly. However, the hash and bucket select can be far faster than traversing a tree, and buckets are cheap, so you can have many, and so few buckets with many pairs. A good hash helps a lot, too.
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LEARN ABOUT NETBSD

checkbashisms

CHECKBASHISMS(1)					      General Commands Manual						  CHECKBASHISMS(1)

NAME

       checkbashisms - check for bashisms in /bin/sh scripts

SYNOPSIS

       checkbashisms script ...
       checkbashisms --help|--version

DESCRIPTION

       checkbashisms, based on one of the checks from the lintian system, performs basic checks on /bin/sh shell scripts for the possible presence
       of bashisms.  It takes the names of the shell scripts on the command line, and outputs warnings if possible bashisms are detected.

       Note that the definition of a bashism in this context roughly equates to "a shell feature that is not required to be supported  by  POSIX";
       this means that some issues flagged may be permitted under optional sections of POSIX, such as XSI or User Portability.

       In  cases  where  POSIX	and  Debian  Policy  disagree, checkbashisms by default allows extensions permitted by Policy but may also provide
       options for stricter checking.

OPTIONS

       --help, -h
	      Show a summary of options.

       --newline, -n
	      Check for "echo -n" usage (non POSIX but required by Debian Policy 10.4.)

       --posix, -p
	      Check for issues which are non POSIX but required to be supported by Debian Policy 10.4 (implies -n).

       --force, -f
	      Force each script to be checked, even if it would normally not be (for instance, it has a bash or non POSIX shell shebang or appears
	      to be a shell wrapper).

       --extra, -x
	      Highlight lines which, whilst they do not contain bashisms, may be useful in determining whether a particular issue is a false posi-
	      tive which may be ignored.  For example, the use of "$BASH_ENV" may be preceded by checking whether "$BASH" is set.

       --version, -v
	      Show version and copyright information.

EXIT VALUES

       The exit value will be 0 if no possible bashisms or other problems were detected.  Otherwise it will be the sum of the following error val-
       ues:

       1      A possible bashism was detected.

       2      A file was skipped for some reason, for example, because it was unreadable or not found.	The warning message will give details.

SEE ALSO

       lintian(1).

AUTHOR

       checkbashisms  was originally written as a shell script by Yann Dirson <dirson@debian.org> and rewritten in Perl with many more features by
       Julian Gilbey <jdg@debian.org>.

DEBIAN
								 Debian Utilities						  CHECKBASHISMS(1)
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