APC is a cache speeding up php execution and allows you to speed up applications by in-memory caching.

Installation of APC on debian / ubuntu

We install the extension using pecl packaging tool (it will download and compile the module).

pecl install apc

If you are asked if you need apxs say no.

Make sure module is enabled in php.ini for command line interface. On debian like systems check if installer did not add anything to /etc/php5/cli/conf.d or /etc/php5/cli/php.ini

If there is no mention of apc.so edit

/etc/php5/cli/php.ini

Enabling APC for the command line interpreter

We have to add just two lines to the appropriate ini file:

apc.enabled = 1
apc.enable_cli = 1 

Now you can check if command line php really loads it by executing

php -i | grep 'apc'

If it shows anything then you are done, otherwise you have to make sure you are editing the correct ini file so try to look for ini path in

php -i