Content
11.7 RECAP
- Since the kernel is protected block in memory, so we must pass "shell" will we enter the name of the Kernel communication, so Kernel can control hardware to work correctly.
- There are reasons for learning the shell: shell command line interface are the same in the major distribution; command line interface for remote management faster; shell Linux system management is very important part, because a lot of control within Linux are written in shell of.
- Legal shell systems are written in the / etc / shell file
- The user's default shell made of record in the / etc / passwd in the last field
- bash main function of editing commands, command and file-completion, command aliases device functions, job control, foreground, background control, programming scripts, wildcard
- Run type can be used to find what type, which can be used with the same functionality
- In other variables is a set of characters or symbols to replace some or a string of data provided reserved
- There are variable environment variables and custom variable, global variable or a local variable called
- Env export or use environment variables to see which variables export may be converted into a custom environment variables
- You can view the current set of all the variables under bash environment
- $? Is also variable, is the return code before and after a command is executed. Executed successfully 0 represents the return code in Linux
- language locale can be used to view data
- Available allow users to read values from the keyboard input variables
- ulimit may be used to limit the user uses the system's resources
- bash profile login shell and is divided into non-login shell. login shell main reading / etc / profile and ~ / .bash_profile, non-login shell then only read ~ / .bashrc
- There are wildcard *? [] Etc.
- Data flow redirection> 2>, information symbols <like to be output to another device or file
- && || treated like symbols; consecutive commands executed by
- Key pipeline command is that it Jinhui processing standard output, to the standard error output will be ignored. Pipe command must be able to receive data from a previous command becomes standard input to continue processing the job.
- This chapter describes the command of the main pipeline cut, grep, sort, wc, uniq, tee, tr, col, join, paste, expand, split, xargs, etc.
Daily Task
Eventually, you'll get old, and I will be crowned king.