Shulou(Shulou.com)06/02 Report--

content points

Condition test:

file test

integer test

String vs. Logic Test

If statement:

If single branch statement

If double branch statement

If multi-branch statement

I. Conditional test:

text command: tests whether a specific expression is true. When the condition is true, the return value of the test statement is 0, otherwise it is other values.

Format 1: test conditional expression Format 2:[conditional expression]

1. Document testing

file comparison

[operator file or directory]

Common test operator L:

-d: test whether it is a directory-e: test whether a directory or file exists-f: test whether it is a file-X: test whether the current user has execution permission-r: test whether the current user has read permission-W: test whether the current user has write permission

2, integer test:

Compare integer values:

Method 1: [integer 1 operator integer 2] Method 2: [$ (integer 1) operator integer 2] Method 3: [integer 1 operator integer 2]

Common test operators:

-eq: equal to-ne: not equal to-It: less than-gt: greater than-le: less than or equal to-ge: greater than or equal to

Test whether the file exists or not, if it does not exist, create it

Details of use:

3. String and logic test:

string comparison

Format 1:[String 1 = String 2 ] [String 1 != String 2 ] Format 2:[-z string]

Common test operators:

=: string content is the same! =: String content is different-z: String content is empty

Logic test:

Format 1:[Expression 1 ] Operator [Expression 2 ]... Format 2: Command 1 Operator Command 2...

Common logical test operators

-a or &&: logical and, meaning "and"-o or||: logical or, meaning "or"!: logical no

If statement:

if single branch

If double branching:

If multiple branches:

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