I needed to do this when I want to debug my scripts for memory usage. My problem at that time was that as I include libraries, for some reasons PHP uses more memory even though I haven’t run a single code (other than require_once).

So my idea is to add memory_get_usage() function call on the beginning of each files. Moreover, that function call should appear in the beginning of a file.

This, apparently poses some problems. Some searches on Google found no real solutions to a quick howto in appending line(s) to the beginning of a file. Many of them have ways to append to the end of file, which is already built-in in Unix-like (read Linux, MacOS X, FreeBSD, etc) operating system. In case you don’t know, use >> operator to append a line to a file. For example, to add new line to the end of existing file test.txt,

What we are working towards

Rather than giving bogus / made-up example, I thought I’d post what exactly I needed. As you recall, I need to add memory_get_usage() function call to the beginning of file. Ideally the output of that function call is

• Saved to some log file so it’s easy for me to look at.
• Includes the file name so I know what file is the culprit.
• For easier to read, display the memory in megabytes instead of bytes.

Having considered all the above requirements, here’s the PHP script I came up with.

error_log(
	__FILE__ . " "
		. number_format(memory_get_usage(true) / (1024 * 1024), 2)
		. " MBn",
	3,
	"/tmp/script_memory_usage"
);

Save the following script as some temporary file. I named it as jajal.sh.

sed '1i<?php error_log(__FILE__ . " " . \
number_format(memory_get_usage(true) / (1024 * 1024), 2) . \
" MBn", 3, "/tmp/vas2"); ?>' $1 > /tmp/jajal.php && \
mv /tmp/jajal.php $1

Then find all PHP codes to append.

Alternatively, you can also use for loop built-in with the shell. This way, you don’t really need to have temporary shell script (that jajal.sh script above)

The above works on Linux. If you’re working on other OS, you may need to modify your sed command like below:

Just for completeness sake … we may want to revert what we did above. So below is the counterpart; to delete the first line from specified files.

There you have it. And as always, I welcome comments / questions / critics that will help me and other readers understand better.