File descriptors and permissions

# File descriptors So what are file descriptors
In linux everything is a file
be a pdf, a keyboard, a screen, literally anything
File descriptors are like ‘a thing’ to the kernel to know what to do with it, it may be a file system, hardware or anything. The standard ones are:
0 -stdin
1 -stdout
2 -sterr
# File permissions Each file has certain permissions to a user and it’s group:
Read -r
write -w
execute.-x \