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Top Forums Shell Programming and Scripting Question on using "[[ ]]" in lieu of IF Construct Post 302284744 by otheus on Friday 6th of February 2009 08:50:29 AM
Old 02-06-2009
Actually, it's not the ""[[ ]]" construct nor the "[ ]" construct, but the && construct that does the trick. There is no standard way, however, of doing negation in the UNIX shell using the && || constructs. One can, however, do something like this:
Code:
not() { 
  "$@"
  if [ $? = 0 ]; then return 1; else return 0; fi
}

# not true || echo false
false
# not false && echo true
true

You can also group things together between { }:
Code:
# not true || { echo false; date; echo really false; false; } || echo Total failure.
false
really false
Total failure.
# not true || { echo false; echo really false; true; } && echo not a total failure.
false
really false
not a total failure.

Does that help?

You should be able now to do:
Code:
command_A && { command_A_worked; command_A_worked_report; true; } || { command_A_failed; command_A_failed_report; false; }

 

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IS_INT(3)								 1								 IS_INT(3)

is_int - Find whether the type of a variable is integer

SYNOPSIS
bool is_int (mixed $var) DESCRIPTION
Finds whether the type of the given variable is integer. Note To test if a variable is a number or a numeric string (such as form input, which is always a string), you must use is_numeric(3). PARAMETERS
o $var - The variable being evaluated. RETURN VALUES
Returns TRUE if $var is an integer, FALSE otherwise. EXAMPLES
Example #1 is_int(3) example <?php $values = array(23, "23", 23.5, "23.5", null, true, false); foreach ($values as $value) { echo "is_int("; var_export($value); echo ") = "; var_dump(is_int($value)); } ?> The above example will output: is_int(23) = bool(true) is_int('23') = bool(false) is_int(23.5) = bool(false) is_int('23.5') = bool(false) is_int(NULL) = bool(false) is_int(true) = bool(false) is_int(false) = bool(false) SEE ALSO
is_bool(3), is_float(3), is_numeric(3), is_string(3), is_array(3), is_object(3). PHP Documentation Group IS_INT(3)
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