Usefull command for Linux Developers

Locating a variable, function or finding a variable, or finding the occurrence / usage of function / variable in an efficient way. For example, you want to find the header file which defines a constant “PATH_MAX”.

    find / -iname *.h | xargs grep -Hn “PATH_MAX”

    or, if you want to redirect the errors, then

    find / -iname *.h 2> /dev/null | xargs grep -Hn “PATH_MAX”