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The Filter Builder is a tool for constructing filters and, optionally,
altering the contents of text-based files, such as log and XML files. Search
and replacement criteria can be specified, and then applied on a line-by-line
basis to the input.
The Filter Builder is useful for tasks such as searching log files, tweaking
regular expressions and renaming variables throughout source files for a
Perl program.
The Filter Builder can filter text documents using either strings or
Perl5 regular expressions. Filters created with the Filter Builder can be
saved as Perl scripts and run from the command line.
Input can be entered or pasted into the Input pane or loaded from files.
The Output pane displays the filtered results. Both input and output can
be saved to a file. The filters created with the Filter Builder can be saved
as Perl scripts.
The Select Lines from Input, Input and Output panes are displayed
by default when the Filter Builder launches. Use the View menu to display
additional panes and to toggle the display of all panes. Resize panes by
clicking on the bars that separate the various panes. Hide unwanted panes
by clicking the 'X' in the top right corner of each pane.
To launch the Filter Builder:
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Select Start|Programs|ActiveState Perl Dev Kit 7.x|Filter Builder
The Filter Builder searches and matches based on the text displayed in the
Input pane. Text can be typed directly into the Input pane, copied
and pasted from another application ('Ctrl'+'C', 'Ctrl'+'V') or copied from
the Filter Builder's own Output pane (Edit|Copy Output to Input).
Input can also be loaded as a file (.txt, .log, .pl, etc). To make text with
long lines easier to read, on the View menu, click Wrap Lines.
To load input from a file:
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On the File menu, select Open|Input File..., or click the 'load
input' icon at the top of the Input pane.
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Select a file using the Load Input dialog box, and click Open. The
contents of the file are displayed in the Input pane.
Note: If you have edited the contents of the input file but want to reload
the original file, on the File menu, select Reload|Input. This command
is only available if the input was loaded from a file.
To load remote input from a URL:
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On the File menu, select Open|Input Location....
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Enter the URL (HTTP, HTTPS, or FTP). For example:
ftp://example.org/pub/remotefile.log
To save changes to the input, use the Save|Input and Save|Input As
commands on the File menu.
To delete the contents of the Input pane, click the 'clear input' icon at
the top of the Input pane. To clear the contents of all panes, and return
to the Filter Builder's default view, select File|New.
The Select Lines from Input pane is displayed by default when the Filter
Builder launches. The Select Lines from Input pane contains a drop-down
list for narrowing filter criteria as well as a check box to make matches
case-sensitive or case-insensitive and a button to set the highlighting
color for filtered text.
The Select Lines from Input pane accepts both strings and Perl5 regular
expressions. Select an option from the drop-down list to define the nature
of the filter. The first four options (containing, not containing,
starting with, not starting with apply to string-based filters, and
the last two (matching, not matching) are for use with regular
expressions.
To create a 'select' filter:
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On the drop-down list, click the item that defines the filter.
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Enter the string or regular expression in the field provided. The check box
to the left of the drop-down list is automatically selected. The results are
automatically displayed in the Output pane. Any text that matches the
filter criteria is highlighted.
By default, this pane contains only one 'selector' (set of options consisting
of an input field and buttons), but others can be added by clicking the
'plus' button in the top right corner of the pane. By adding selectors, you
can create a filter with multiple conditions.
The Or and And radio buttons determine the boolean relationship
between multiple conditions (i.e. 'this' AND 'that' vs. 'this' OR
'that').
The Replace Regular Expression pane accepts Perl5 regular expressions.
Select View|Replace to display this pane.
To create a 'replace' filter:
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In the first field, enter the regular expression to be replaced.
The check box to the left of this field is automatically selected. The
initial results are automatically displayed in the Output pane.
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In the second field, specify the replacement for the regular
expression. The results are automatically displayed in the Output pane.
Any text that matches the filter criteria is highlighted.
Use the options to the right of the fields in the Replace Regular
Expression pane to further refine the replacement criteria. Clear the
Global check box to replace the first instance in a
given line (the default is to replace all occurrences
in each line). Clear the Ignore case check box to make the
match case-sensitive. Click the 'select color' button set the highlighting
color for the filtered text that appears in the Input and Output
panes.
By default, the Replace Regular Expression pane contains only one
'selector' (a set of replacement fields and buttons for additional
options). Click the 'plus' button in the top right corner of the pane to
create additional selectors. Adding selectors makes it possible to create
a filter with multiple conditions. Select different check boxes to
experiment with various filter combinations.
Use the Variables pane to specify elements of regular expressions that
will be provided to the filter script as arguments. Replace the parts of
regular expressions in the Select Lines from Input and Replace Regular
Expression panes with the variable name. Once these variables have been
created and tested with the Filter Builder, they can be initialized from
the command line.
Select View|Variables to display the Variables pane.
To create a variable filter:
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In the Variables pane, click the 'add' button. The New Variable dialog
box is displayed.
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Enter a name for the variable, and click OK. The variable name must
conform to Perl syntax. That is, the first two characters must be a dollar
sign and some letter (e.g. $a). Add other letter and numbers as desired to
complete the variable name (e.g. $arg1). An entry is added to the
Variables pane.
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Enter the value for the variable, and select Save|Filter As. Once the file
has been saved, the location of the filter is displayed in the Filter
Builder's status bar.
You can save filters so that they may be re-opened in the Filter Builder. To
save changes to a newly created filter as a Perl file, select
File|Save Filter As. To save changes to a previously saved filter, select
File|Save Filter.
When saving a filter, you may want to add an explanation of its purpose.
Select View|Description Pane to display the Description pane. Click in the
Description pane, and then type or paste the description into the
pane. The text is saved along with the contents of a filter.
Filters created in the Select Lines from Input, Replace Regular
Expression, and Variables panes can be saved as Perl files and then
re-opened whenever necessary. To open a previously saved filter, on the
File menu, select Open|Filter. Use the Open Filter dialog box to
navigate to the filter location.
To close a saved filter, on the File menu, click New. The existing
filter closes, and a new set of the current panes is displayed.
The contents of the Input and Output panes can be saved to disk. When saving
input, select File|Save|Input As. To save changes to existing input, select
File|Save|Input. Output can be saved in a variety of file formats but
cannot be edited. To save output, click the 'save' button at the top right
of the Output pane. Alternatively, use File|Save|Input As or
File|Save|Input.
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