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  • [bash] Condition Tests





    Table 5-3. Arithmetic test operators

    Test

    Comparison

    -lt

    Less than

    -le

    Less than or equal

    -eq

    Equal

    -ge

    Greater than or equal

    -gt

    Greater than

    -ne

    Not equal


    Table 5-2. File attribute operators

    Operator

    True if...

    -a file

    file exists

    -d file

    file exists and is a directory

    -e file

    file exists; same as -a

    -f file

    file exists and is a regular file (i.e., not a directory or other special type of file)

    -r file

    You have read permission on file

    -s file

    file exists and is not empty

    -w file

    You have write permission on file

    -x file

    You have execute permission on file, or directory search permission if it is a directory

    -N file

    file was modified since it was last read

    -O file

    You own file

    -G file

    file's group ID matches yours (or one of yours, if you are in multiple groups)

    file1 -nt file2

    file1 is newer than file2 [6]

    file1 -ot file2

    file1 is older than file2


    [6] Specifically, the -nt and -ot operators compare modification times of two files.


    Table 5-1. String comparison operators

    Operator

    True if...

    str1 = str2[4]

    str1 matches str2

    str1 != str2

    str1 does not match str2

    str1 < str2

    str1 is less than str2

    str1 > str2

    str1 is greater than str2

    -n str1

    str1 is not null (has length greater than 0)

    -z str1

    str1 is null (has length 0)


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  • 原文地址:https://www.cnblogs.com/friedwm/p/2133712.html
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