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true(1) [bsd man page]

TRUE(1) 						      General Commands Manual							   TRUE(1)

true, false - provide truth values SYNOPSIS
true false DESCRIPTION
True and false are usually used in a Bourne shell script. They test for the appropriate status "true" or "false" before running (or fail- ing to run) a list of commands. EXAMPLE
while true do command list done SEE ALSO
csh(1), sh(1), false(1) DIAGNOSTICS
True has exit status zero. 7th Edition April 29, 1985 TRUE(1)

Check Out this Related Man Page

IS_STRING(3)								 1							      IS_STRING(3)

is_string - Find whether the type of a variable is string

bool is_string (mixed $var) DESCRIPTION
Finds whether the type given variable is string. PARAMETERS
o $var - The variable being evaluated. RETURN VALUES
Returns TRUE if $var is of type string, FALSE otherwise. EXAMPLES
Example #1 is_string(3) example <?php $values = array(false, true, null, 'abc', '23', 23, '23.5', 23.5, '', ' ', '0', 0); foreach ($values as $value) { echo "is_string("; var_export($value); echo ") = "; echo var_dump(is_string($value)); } ?> The above example will output: is_string(false) = bool(false) is_string(true) = bool(false) is_string(NULL) = bool(false) is_string('abc') = bool(true) is_string('23') = bool(true) is_string(23) = bool(false) is_string('23.5') = bool(true) is_string(23.5) = bool(false) is_string('') = bool(true) is_string(' ') = bool(true) is_string('0') = bool(true) is_string(0) = bool(false) SEE ALSO
is_float(3), is_int(3), is_bool(3), is_object(3), is_array(3). PHP Documentation Group IS_STRING(3)
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