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Full Discussion: Test condition
Top Forums Shell Programming and Scripting Test condition Post 302252067 by gio001 on Tuesday 28th of October 2008 05:27:10 PM
Old 10-28-2008
Test condition

Hello,
what is the better and correct way to perform a comparison:
I have been using the following with no problems:

if [[ $a = "" ]]
then ....
fi

I have seen this also used :
if [ $b -eq 1 ]
then ....
fi

When I try :
if [ $a = "" ]
then ....
fi

I get an error like .... the test condition expects a parameter.
Can anybody explain? Is it due to the data types and different type allow different comparison constructs?

Thanks!
 

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AUSEARCH_ADD_TIMESTAMP_ITEM(3)					  Linux Audit API				    AUSEARCH_ADD_TIMESTAMP_ITEM(3)

NAME
ausearch_add_timestamp_item - build up search rule SYNOPSIS
#include <auparse.h> int ausearch_add_timestamp_item(auparse_state_t *au, const char *op, time_t sec, unsigned milli, ausearch_rule_t how) DESCRIPTION
ausearch_add_timestamp_item adds an event time condition to the current audit search expression. The search conditions can then be used to scan logs, files, or buffers for something of interest. The op parameter specifies the desired comparison. Legal op values are <, <=, >=, > and =. The left operand of the comparison operator is the timestamp of the examined event, the right operand is specified by the sec and milli parameters. The how value determines how this search condition will affect the existing search expression if one is already defined. The possible val- ues are: AUSEARCH_RULE_CLEAR Clear the current search expression, if any, and use only this search condition. AUSEARCH_RULE_OR If a search expression E is already configured, replace it by (E || this_search_condition). AUSEARCH_RULE_AND If a search expression E is already configured, replace it by (E && this_search_condition). RETURN VALUE
Returns -1 if an error occurs; otherwise, 0 for success. APPLICATION USAGE
Use ausearch_add_item(3) and ausearch_add_interpreted_item(3) to add conditions that check audit record fields. Use ausearch_add_expres- sion(3) to add complex search expressions using a single function call. SEE ALSO
ausearch_add_expression(3), ausearch_add_item(3), ausearch_add_interpreted_item(3), ausearch_add_regex(3), ausearch_set_stop(3), ause- arch_clear(3), ausearch_next_event(3), ausearch-expression(5). AUTHOR
Miloslav Trmac Red Hat Nov 2007 AUSEARCH_ADD_TIMESTAMP_ITEM(3)
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