Setting permanent alias for "composer"

Dear tech-pros,

first see this:

When I create an alias the command "composer" works as expected, locally.
The script which is executed after the elgg-folder was created (.scripts/check_global_requirements.php) doesn't know the alias anymore. I stored the alias as well in the .bashrc (there is no .profile or .bash_profile). The error is "sh: composer: command not found"

Another idea: in the script (.scripts/check_global_requirements.php) the command is executed via "exec". As far as I know I do have to change the PHP mode from native PHP (apache) to CGI-PHP to run the command "exec". This I can do via "AddHandler php5-cgi .php" in a .htaccess-file, which has to be stored in the project-folder. Now the folder isn't empty anymore and an install isn't possible anymore (requires empty directory). [Adding the handler one folder above should work for this]

Any ideas on this? Thanks in advance!