logic conditional symbol

A macro resembles a function in C, executes after the specified parameter is passed in, and inside the macro can contain the data step program and the conditional operation symbol.A macro variable is just a small variable 、、、、 (by the same is a

Shell and Export commands After the user logs on to the Linux system, a user shell is started. In this shell, you can use shell commands or declare variables, or you can create and run shell script programs. When you run the shell script program,

# Well No. (comments)#管理员 $ ordinary User In the script #!/bin/bash #!/bin/sh Typically appear in the first line of the shell script, meaning to use/bin/bash to execute the current shell script, except for the first line, which plays the role of

The special symbols commonly used in the shell are listed below:#   ;      ;;      .       ,/\ ' String ' |   !      $   ${}   $?   $$ $* "String" * * *?   : ^ $# [email protected] ' command ' {} [] [[]] () (()) | | && {Xx,yy,zz,...} ~ ~+ ~-& \ +-%=

If statement formattingIf conditionThenCommandElseCommandFi, don't forget this ending.If statement forgets the end fiThree conditional expressions of Test.sh:line 14:syntax error:unexpected end of Fi if IfCommandThen ifFunctionThenCommand executed

logical operators A logical operator that combines an expression containing a relational operator to form a new expression; The result is either true or false, and the result value is stored with the BOOL type variable.

If statement formatIf conditionThenCommandElseCommandFi, don't forget this ending.If statement forget the end fiTest.sh:line 14:syntax error:unexpected End of fi if three conditional expressionsIfCommandThen ifFunctionThenCommand execution succeeds,

Conditional judgment is the basis for a program to gain intelligence, while the Bourne shell script simulates conditional expressions in most programming languages by command.The control structures supported in the shell are:(1) If then else fi(2)

Web| News Brief introduction The requirements of business applications always change with the changing trend of the business environment. Decisions are rarely immutable, and competitive pressures require flexibility in the design and implementation

Section III: The wording of conditional judgmentIf conditional judgment, the "conditional judgment" in the grammatical structure of if can have many forms. The test result is true, just to see if it returns a value of 0.The following 10 types of