Linux Basic Instruction __linux

Linux First bullet

1. Learning of basic Instructions

ls-all lists all hidden files and related file attributes

Date shows current system time
Format output:
Date +%y/%m/%d 2018/04/13
Date +%h:%m 11:17

echo $LANG View the current language and character encoding format
If we need to change the language of the English language family
Then: Lang=en_us

4 instructions for displaying the calendar cal
cal [Month][year]
Cal 2018 shows calendar of the year
Cal 04 2018 shows the April 2018 calendar

5. Calculator instruction BC
Enter BC in the instruction column to enter the calculator software environment
1/10
0
The output here is 0, because the BC preset outputs only integers, and if you want to output decimal digits
You need to perform scale=number number to indicate the decimal digits of the output
Example:scale=3
1/3
.333

There are two situations when you give commands in instruction mode
One: This instruction will display the result directly, then return to the command prompt and wait for the next instruction input.
Two: Enter the instruction environment, end the instruction environment and return to the command prompt environment