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Full Discussion: perl - how come this script works?
Top Forums Shell Programming and Scripting perl - how come this script works? Post 302136329 by mjays on Monday 17th of September 2007 06:28:19 AM
Old 09-17-2007
perl - how come this script works?
Code:
#!/usr/bin/perl
open (DATA, file.txt);
@array = <DATA>;
close (DATA);

open (DATA, ">$file.txt");
for (@array) {
      s/text/replace text/;
      push(@contents,$_);
}
seek(DATA, 0, 0);
print DATA (@contents);

close(DATA);

could someone please explain how this works. i've been trying for awhile now to find out how to open a file, replace some text and then save the file. i eventually found the code above.

however, as far as i knew 'push' placed an item onto the end of an already defined array, but in the code above @contents isn't defined.

what's going on?

regards,

matt
 

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LEARN ABOUT SUSE

alter_foreign_data_wrapper

ALTER FOREIGN DATA 
WRAPPER(7)					   SQL Commands 				     ALTER FOREIGN DATA WRAPPER(7)

NAME

       ALTER FOREIGN DATA WRAPPER - change the definition of a foreign-data wrapper

SYNOPSIS

       ALTER FOREIGN DATA WRAPPER name
	   [ VALIDATOR valfunction | NO VALIDATOR ]
	   [ OPTIONS ( [ ADD | SET | DROP ] option ['value'] [, ... ]) ]
       ALTER FOREIGN DATA WRAPPER name OWNER TO new_owner

DESCRIPTION

       ALTER  FOREIGN  DATA  WRAPPER  changes  the  definition of a foreign-data wrapper. The first form of the command changes the library or the
       generic options of the foreign-data wrapper (at least one clause is required). The second form changes the owner of the foreign-data  wrap-
       per.

       Only superusers can alter foreign-data wrappers. Additionally, only superusers can own foreign-data wrappers.

PARAMETERS

       name   The name of an existing foreign-data wrapper.

       VALIDATOR valfunction
	      Specifies a new foreign-data wrapper validator function.

	      Note  that it is possible that after changing the validator the options to the foreign-data wrapper, servers, and user mappings have
	      become invalid. It is up to the user to make sure that these options are correct before using the foreign-data wrapper.

       NO VALIDATOR
	      This is used to specify that the foreign-data wrapper should no longer have a validator function.

       OPTIONS ( [ ADD | SET | DROP ] option ['value'] [, ... ] )
	      Change options for the foreign-data wrapper. ADD, SET, and DROP specify the action to be performed. ADD is assumed if  no  operation
	      is explicitly specified. Option names must be unique; names and values are also validated using the foreign data wrapper library.

EXAMPLES

       Change a foreign-data wrapper dbi, add option foo, drop bar:

       ALTER FOREIGN DATA WRAPPER dbi OPTIONS (ADD foo '1', DROP 'bar');

       Change the foreign-data wrapper dbi validator to bob.myvalidator:

       ALTER FOREIGN DATA WRAPPER dbi VALIDATOR bob.myvalidator;

COMPATIBILITY

       ALTER  FOREIGN DATA WRAPPER conforms to ISO/IEC 9075-9 (SQL/MED). The standard does not specify the  VALIDATOR and OWNER TO variants of the
       command.

SEE ALSO

       CREATE FOREIGN DATA WRAPPER [create_foreign_data_wrapper(7)], DROP FOREIGN DATA WRAPPER [drop_foreign_data_wrapper(7)]

SQL - Language Statements					    2010-05-14					     ALTER FOREIGN DATA WRAPPER(7)
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