Linux basic Commands (i)

Linux basic commands

Editor vim
Compiler GNU Tool chain-GCC
Debugger GDB
The operating system is written in C.

system programming (core skeleton 80%)
file I/o
file system
process {Process Control primitives, interprocess communication, inter-process relationships
signal
thread {thread control primitives, thread synchronization mechanism
network programming {socket sockets, TCP/IP/UDP, Concurrent server development (multi-process concurrency, multithreaded concurrency, asynchronous I/O (epoll, select, poll))

Shell Programming {Regular expression
Database

GNU founder Richard Matthew Stallman

Shell: Command interpreter, executes the command according to the command entered

Wu Ban Figure 14.04

Cat/etc/shells

Bash is the default shell for Linux

tab command and path completion

History record, you can also move the cursor key up or down

Main keyboard shortcuts
Ctrl+e or end cursor moves to the end of the statement

Del Delete after the cursor
BACKSPACE delete the cursor in front of the

UNIX-like system directory structure

Ubuntu does not have the concept of a drive letter, only one root directory/
Ls

boot store startup information, kernel and boot program grub
dev device driver files, mouse, keyboard, network cards, etc. in Linux are called files
etc Common configuration information
home User home directory
media u disk, such as
mnt empty directory can be mounted
opt empty, can be installed some software such as QQ
sbin executable
var variable

Cat is used to read a file

cd Change dir

User directory located in/home/user

Cd-, back from where?

Relative path (described from the current position) and absolute path (from/directory start description)

.. The top level directory, the parent directory
. Represents the current directory

LS is a shorthand for the English word list

-a lists hidden files that start with a. file that is hidden
Touch to create a file
-L detailed list, create time, size, user, permissions
-R is listed along with the contents of subdirectories

Blue is the directory, green executable program, Red compress package

A directory defaults to 4096 or 4096 integer times

User name and user group

The highest bit is used to describe the type of file:
D catalog File
-Normal file
L symbolic link, similar to a shortcut under Windows
B-Block device files
C-character device file mouse keyboard
s socket file, network sockets
P Pipe

The first one is the owner the second is all groups third is the other group
RWX Read and write execution

Linux basic Commands (i)