Linux reminders

Mount

showmount -e <remote_machine_ip>

#mount /var/tmp in our machine

mkdir /mnt/kenobiNFS
mount machine_ip:/var /mnt/kenobiNFS
ls -la /mnt/kenobiNFS

SSH with key

chmod 600 id_rsa
ssh -i id_rsa <user>@<ip>

SUID / SGID / Sticky Bit

Permission	On Files	On Directories
SUID Bit	User executes the file with permissions of the file owner	/
SGID Bit	User executes the file with the permission of the group owner	File created in directory gets the same group owner
Sticky Bit	No meaning	Users are prevented from deleting files from other users

File descriptors

Integer value	Name	<unistd.h> symbolic constant	<stdio.h> file stream
0	Standard input	STDIN_FILENO	stdin
1	Standard output	STDOUT_FILENO	stdout
2	Standard error	STDERR_FILENO	stderr