It means that in linux, when typing a command like
the shell (bash most likely) will search only your PATH environment for that executable.
This means that even if you are in the directory in which a executable resides, you can't execute it just by typing it's name. To circumvaint this, linux users usually type
Code:
./name_of_the_executable_file
or
Code:
/full/path/to/executable/file
You can, however, add the current directory to the path by adding
./ (or simply
.) in the PATH environment.. However this is very bad practice for root..
Consider that a tricky user made a malicious script that changed the password of the root account (or does any other thing) and named that program
cd or
ls and put it in his home folder... Then consider a newby sys-admin that allowed the following PATH for root
Code:
PATH=.:/sbin:/usr/sbin:/bin:/usr/bin
Now, if he ever founds himself in that users home directory and uses the
cd or
ls commands, that malicious programs will get executed instead (well, in this exact situation, in a typical system, bash already found
cd once in /usr/bin/cd and won't look for it again -- but that's another discussion)
Hope I've cleared things up a little..