Linux shell programming ---- judgment + operator

Linux shell programming ---- judgment + operator 1 judgment 1 simple if statement if expression then statement fi if then is in the same line, add "; "2 if/else structure if expression then statement else statement fi 3 if/elif/else structure if expression then statement elif statement else statement fi 4 case structure case variable in value1) statement; value2) statement ;;.......................... *) statement; the variable value variable of the esca case structure is compared with value1, value2, and so on one by one until matching values are found. If no matching value is found, the default value *, each branch ends with a double Semicolon ";". In Linux Shell, Operator 1 includes the following Arithmetic Operators: +,-, *,/, %, ** 2 Arithmetic Operator example result + 3 + 5 8-5-3 2*5*3 15/8/3 2% 8% 3 2 ** 5 ** 3 125 3 Linux Shell the let Command is a built-in operation used to calculate integers, suppose I have defined two integer variables a and B, then I can use the let command to perform the operation, let c = a + B, let c = a-B, and so on. The four-bit operator 1-bit operation is rarely used in Shell, and is usually used for integer operations, bitwise operations are performed on the bitwise in the binary data stream where integers are stored in the memory. Two common bitwise operators are <(left shift),> (right shift ), & (bitwise AND) and so on