Raspberry Pi_Eng_10.10.1 “date” Command- Confirm & Change Time Information

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10.10 Commands Related to System Information

10.10.1 “date” Command- Confirm & Change Time Information

The time zone set in the current system can be changed using “raspi-config” command. For details, refer to the description of [9.2 How to Configure the System].

If the system is connected to the Internet, it will connect to the time server on the network and set the time automatically. This configuration is handled automatically each time the system boots. Therefore, even if you change the time manually, the next time you boot, it will be reset to the time of time server.

On Linux, use the “date” command to directly query or adjust the system date and time.

Raspberry Pi_Eng_10.1.4 Utilizing Command Execution History

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10.1.4 Utilizing Command Execution History

When working at the Terminal, you may work a task repeatedly on multiple files, or work multiple tasks on a specific file. In addition, there are times when you need to reconfirm what tasks you have done previously in multiple steps. In some cases, you may want to correct partially and rework the command in case the input is wrong and an error occurs. When you execute various commands, it is useful to know the history of commands that you have executed before.

Raspberry Pi_Eng_10.1.3 Quoting Rule

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10.1.3 Quoting Rule

10.1.3.1 Overview of Quoting Rule

Quoting is to enclose a string with quotation marks. The reason for doing this is to prevent the special characters from being reinterpreted or expanded by the Shell or Shell script when special characters are included in the string. For reference, “special character” refers to a character that can be interpreted differently from the meaning of a character. For example, the wildcard character “*” is a special character.

Raspberry Pi_Eng_10.1.2 Special Key of Shell

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10.1.2 Special Key of Shell

In Shell, special keys are defined in advance to perform special functions.

key

function

description

ctrl+d

terminate input

Same as logout or exit. Log out of the shell (similar to exit).
“EOF” (End of file, end the foreground job).
End incoming input from standard input.

ctrl+c

terminate program

terminate a running program

ctrl+z

switch to background

Switch the running job to background and pause.

ctrl+s

halt screen output

halt screen output

ctrl+q

resume screen output

Restart screen output interrupted by ctrl + s

Raspberry Pi_Eng_10.1.1 Standard Input and Output

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10.1 Command Overview

10.1.1 Standard Input and Output

In the Shell, a standard device is already specified for the input device that receives the input data for execution and the output device for which the processing result is displayed. Therefore, unless there is a specific designation, data is always input from the standard input device, and the processing result is always output to the standard output device.

Raspberry Pi_Eng_10.0 Chapter 10 Understanding Shell Command

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Chapter 10 Understanding Shell Command

Chapter’s Main Topics

This chapter describes the Shell command. It will first explain the basics of the Shell command, explain how to use the Shell command, and then describe the most basic Shell commands. We will not cover all the Shell commands here, and commands associated with a particular topic will be discussed together when dealing with the topic.

It includes descriptions on the following topics:
■ Command overview

■ Shell environment

■ Shell and profile

■ Basic command

■ Operation processing related commands

■ Selective execution related commands

■ Program execution related commands

■ Input and output adjustments related commands

■ Data manipulation related commands

■ System information related commands