Shell Judgment Statement

1. String judgment

STR1 = str2 When two strings have the same content, length is true
Str1! = str2 True when string str1 and str2 are not equal
-N str1 True when the length of the string is greater than 0 (string non-null)
-Z str1 True when the string length is 0 (empty string)
STR1 is True when string str1 is not empty

2, the number of the judgment

Int1-eq int2 Two numbers equal to True
Int1-ne Int2 Two number is true
INT1-GT Int2 int1 greater than Int2 is true
Int1-ge Int2 int1 greater than or equal to Int2 true
Int1-lt Int2 int1 Less than Int2 is true
Int1-le Int2 int1 less than or equal to Int2 true

3 Judgment of the document

-r file user readable as True
-W file user can write as true
-X file user can execute as true
-F file is true for regular files
-d file files are directory-True
-C File file is true for character special files
-B file files are true for block special files
-S file files non-0 o'clock True
-T file is true when the specified device is terminal (default = 1)

3. Complex logic judgment

-A and
-O or
! Non -

Shell Judgment Statement