Redirect Standard Output

By completing this chapter, you can do the following things: Change the output of the Unix command to the file. Prints the error message generated by the UNIX command to the file. Change the input of UNIX commands. Define a filter using some basic filters such as Sort,grep and WC. 9.1 Input and output REDIRECT Introduction shell provides the ability to redirect the input and output of a command. The output of most commands is output to the terminal screen, such as date,ls,who and so on, many commands are entered from the keyboard, commands include mail ...

Executing a shell command line typically automatically opens three standard files, namely standard input files (stdin), usually the keyboard of the terminal, standard output files (stdout), and standard error output files (stderr), which correspond to the screen of the terminal. The process obtains data from the standard input file, outputs the normal output data to the standard output file, and sends the error message to the standard error file. As an example of the cat command, the function of the Cat command is to read the data from the file given in the command line and send it directly to the standard ...

By completing this chapter, you will be able to do the following: Understand the purpose of a pipe to create a pipe that obtains output from one command, and then manufactures input for another command using Tee,cut,tr,more, and PR filter 10.1 pipe profile shell provides the ability to connect commands through pipelines. The flexibility to reflect the operating environment of the UNIX system is fully filtered through the files. You can use pipelines to filter the output of a command. This chapter will introduce the use of pipes, and some filters (Cut,tr,tee and PR), which ...

Linux allows a program to continue running after exiting the login? We can use the Nohup command and the disown command.　Nohup command usage: nohup command [parameters] ... Or: The NOHUP option ignores the suspend signal to run the specified command.    &http://www.aliyun.com/zixun/aggregation/37954.html ">nbsp; ...

To complete this chapter, you can do the following: Understand the workings of the shell describe the user logon process describing user environment variables and the functions of these environment variables. Set up and modify shell variables. Understand and modify some special environment variables such as path, term, etc. Customizing user environment variables for specific applications. 6.1 What is a shell? The shell is an interactive command interpreter. Shell is independent of the operating system, and this design gives users the flexibility to choose the shell that suits their needs. Shell let you in ...

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