So since references to a variable in a command are replaced with (or 'expanded' to) the variable's value by Bash at the time of the command's evaluation, :$PATH is put at the end of the value to be assigned to PATH so that PATH ends up containing ~/.composer/vendor/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games (i.e. Since PATH normally contains something when ~/.profile is sourced (by default it contains /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games), simply setting PATH to ~/.composer/vendor/bin would make PATH contain only ~/.composer/vendor/bin. The first PATH as explained above is the environment variable to be set using export. What is the first PATH and what is the second $PATH, and why do we need two? also other shells, which will in turn be able to access it). in this case to the Bash instance that sources ~/.profile and to all the subprocesses spawned in the same environment (which may include e.g. Is it exporting the data to be available for Bash?Įxport sets the environment variable on the left side of the assignment to the value on the right side of the assignment such environment variable is visible to the process that sets it and to all the subprocesses spawned in the same environment, i.e. it's not an executable present in PATH, it's a command that Bash has built-in in itself). What is this 'export' phrase at the start?Įxport is a command (more precisely it's a Bash builtin, i.e.

What does it mean to extract software