variables
Overview of important variables
$PATH
What is $PATH?
$PATH
is an environmental variable in Linux and Unix-like operating systems which specifies directories that hold executable programs. When the user runs any command in the terminal, it searches for executable files with the help of the PATH Variable in response to commands executed by a user.
It is very simple to view the Path of the relevant user with help of the command "echo $PATH".
$LD_LIBRARY_PATH
LD_LIBRARY_PATH provides a list of directories where shared libraries are searched for first.
LD_LIBRARY_PATH
is the predefined environmental variable in Linux/Unix which sets the path which the linker should look in to while linking dynamic libraries/shared libraries.
LD_LIBRARY_PATH
contains a colon separated list of paths and the linker gives priority to these paths over the standard library paths /lib
and /usr/lib
. The standard paths will still be searched, but only after the list of paths in LD_LIBRARY_PATH
has been exhausted.
The best way to use LD_LIBRARY_PATH
is to set it on the command line or script immediately before executing the program. This way the new LD_LIBRARY_PATH
isolated from the rest of your system
$LD_PRELOAD
LD_PRELOAD loads a shared object before any others when a program is run
If you set LD_PRELOAD
to the path of a shared object, that file will be loaded before any other library
Read more: https://blog.fpmurphy.com/2012/09/all-about-ld_preload.html#ixzz6rx8UeNvh
References
https://tryhackme.com/room/linuxprivesc (Task 7 -
$LD_LIBRARY_PATH
,$LD_PRELOAD
)
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