How does Unix search for executable files?

Solution 1:

The $PATH is searched from beginning to end, with the first matching executable being run. So directories at the beginning of $PATH take precedence over those that come later. Executables in the current directory (.) are only executed if . is in $PATH (which it usually isn't). There is no implicit inclusion of the current directory in the search path.

Solution 2:

For files in the current directory, you will want to precede them with ./, so the command would become ./executable.sh. You should never have . in your PATH as it poses a security risk, among other problems.

Directories that come first in the PATH and searched first.

The overall order for searching is like this if I remember correctly:

• aliases

• exported functions

• built-in shell commands

• scripts and binaries in your PATH