Linux system command analysis

LinuxRegular system tasks are performed by the command, the command line for category have a clear understanding of the in-depth study of the system has a good promoting effect. Linux command Daquan can access the site . Commands are divided into two categories:Built-in command && External command。

Determine whether the command is a built-in command

type command

The following figure shows the built-in whether a command to execute the command, if not to belong to the external command, usually placed in / bin, / usr / bin, / sbin, / usr / sbin ...... and so on.

ShellBuilt-in command

Bash( Bourne Again ShellAbbreviation) as Linuxthe default system Shell, with more than 60 commands. Commonly used are:

• enableShell internal command for temporarily closing or activate designated common enable -adisplay all active builtin
• killKill the process, commonly kill -9 PIDforced to shut down a process
• echo Value for the variable printing, or directly outputs the specified character string
• export A variable output as an environment variable, or a function as an environment variable output
• env System for displaying the existing environment variables, and execution of instructions in a defined environment
• history Instructions for displaying the designated number of command, a read command history file directory to the history and the history command buffer command buffer write command in the File Directory
• w Provides the current logged-on user information and executing processes

Process Commands

• psProcess status for the current reporting system, with killinstruction interrupted at any time, remove unnecessary programs, commonly used ps -aqueries all processes
• pstree In the manner of a tree diagram to show the relationship between the derivation process, display more intuitive

Development Command

• gccBased C/C++compiler, open source applications is the most widely used compiler
• gdb Powerful debugger
• make Engineering compiler tools for source code compiled numerous linked asking price in order to achieve engineering management
• apt-getIs the Debian Linuxrelease of the APTpackage management tools

Network Management Command

• nethogs Open source command line tool (similar to Linux's top command), according to real-time statistical process or program network bandwidth usage
• ifstat A statistical network interface active tool

System Management Commands

• top The overall operation of real-time dynamic view of the system, is a combination of information from multiple utilities to monitor system performance and operational information

Common Commands

• clear It used to clear any information on the current terminal screen
• cd Given folder (or directory) set to the current working directory
• whatis What used to query a command function, and for printing results to the terminal
• date Display or set the system time and date