Embedded design study concluded 2

Embedded Linux operating system
1, install Linux development environment:
vm virtual machine (by means of software simulation pc)
Q: Why not choose a dual system?
Embedded developers to interact with the kernel will cause the system to crash.
2, Linux Introduction (POSIX, GPL, GNU)
the father of the C language: Dennis Ritchie = unix father's (business software)
the POSIX standard: Portable Operating System Interface (cross-platform conditions)
the GNU plan: gun is not unix; (Excellent tools gdb gcc)
Linux use (VS Windows)
Linux positioning: developers (efficiency) win32 positioning: regular user (simple)
goal: from mouse

Linux a little philosophy: everything is a file
classification Linux file:

1. Trivial File: -
2. Catalog File: d
3. Device File: c / b
4. Link files: L
   Linux special files:
5. Pipe file: p
6. Stack file: f
7. Share files: s

Some simple command summary:
root: Superuser (has all rights)
jsetc: ordinary users (restricted)

User management commands:

• su to root
• sudo privileges in exchange for more advanced
• adduser increase user
• Clear user deluser
• passwd to change your password

Command file operations:

• What ls view files in the directory
• chmod file permissions to modify
  operating authority Linux file: R & lt readable, writable W, x execute
  permissions Description: Group 3 - the current user, the current user group, other users
• gedit file editor (vim gvim)
• gcc compiler file (compiler ./a.out)

Directory operations command:

• cd / cd ... Change directory

• mkdir create a new empty directory

• rmdir deletes an empty directory
  root: the parent directory of all files (all files are saved in the root directory)

• bin frequently used commands

• Hypervisor sbin system administrators

• dev file system for all devices

• etc all system configuration files

• root root user's working directory

• Ordinary home users working directory

• Software (libraries, header files) installed in the system user storage

• - the current user's working directory

Absolute and relative paths:
Absolute path: the path of writing, from the root directory / write from, for example: / usr / share / doc directory.
Relative path: the path of writing, not by / write from, for example, the / usr / share / doc when you want to / usr / share / under man, can be written as: cd ... / man

• cp copy a file or directory
• Name mv move files and directories, or modify files and directories