Standard Streams

STD IO Steams are generally used for CLI applications in PHP



The standard input is usually received from the keyboard

Standard out and standard error are usually sent to the screen


Standard In Input from Keyboard stdin 0
Standard Out Output to Screen stdout 1
Standard Error Output to Screen stderr 2


Read a single line from stdin using fgets(STDIN)


	//using the trim() function to remove any leading/trailing whitespace
	$line = trim(fgets(STDIN));


Assuming PHP is available from the command line, you can write to STDOUT using:

php -r 'fwrite( STDOUT, "some text output\n") ; '


note -r means to run the command


Or to write to STDERR:

php -r 'fwrite( STDERR, "some text output\n") ; '



Simple way to tell if PHP is running from the command line is to check the version with:

php -v

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