Shulou(Shulou.com)06/03 Report--

This article mainly introduces "how to use if statements of batch commands". In daily operation, I believe many people have doubts about how to use if statements of batch commands. Xiaobian consulted all kinds of materials and sorted out simple and easy-to-use operation methods. I hope it will be helpful to answer the doubts of "how to use if statements of batch commands". Next, please follow the editor to study!

If is used for conditional judgment and applies to the following situations:

1. To determine whether a drive, file or folder exists, use the if exist statement

2. To determine whether two strings are equal, use the if "string 1" = = "string 2" statement

3. To judge whether two values are equal, use if numerical value 1 equ numerical value 2 statement

4. To determine whether a variable has been assigned, use the if defined str statement

The complete format of the if statement is as follows: if conditional expression (statement 1) else (statement 2), which means that if the conditional expression holds, then statement 1 is executed, otherwise statement 2 is executed.

For the above four cases, you can use the following code:

1. If exist d:\ test.txt (test.txt exists under echo D) else (test.txt does not exist under echo D)

2. If "abc" = = "xyz" (echo string abc equals string xyz) else (echo string abc is not equal to string xyz)

3. If 1 equ 2 (echo 1 equals 2) else (echo 1 is not equal to 2)

4. If defined str (the echo variable str has been assigned to% str%) else (the value of the echo variable str is empty)

When judging whether a string is equal, if will be case-sensitive. For example, a simple if statement will think that the string abc is different from the string Abc. If you do not want to be case-sensitive, you need to add a / I switch, using the format of if / I "string 1" = = "string 2"; in addition, the equal symbol is a continuous "=" rather than a separate "=".

To judge the size relationship between two values, in addition to using equ, there are other relation symbols, all of which are applicable to if statements as shown in the following table:

Chinese meaning

Relation character

English explanation

Equal to

Equ

Equal

Greater than

Gtr

Greater than

Greater than or equal to

Geq

Greater than or equal

Less than

Lss

Less than

Less than or not equal to

Leq

Less than or equal

Not equal to

Neq

No equal

The if statement also has a simplified format: the if conditional expression statement, which means that if the conditional expression is valid, the statement will be executed, otherwise, nothing will be done.

Examples of multi-tier if nesting syntax:

If exist a.txt (if exist 1.txt (echo exists a.txt and 1.txt) else (echo exists a.txt but does not exist 1.txt) else if exist b.txt (echo does not exist a.txt but b.txt) else (echo does not exist a.txt and b.txt) so far, on "how to use the if statement of batch commands" is over, hope to solve everyone's doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.