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  • Valid Phone Numbers

    Given a text file file.txt that contains list of phone numbers (one per line), write a one liner bash script to print all valid phone numbers.

    You may assume that a valid phone number must appear in one of the following two formats: (xxx) xxx-xxxx or xxx-xxx-xxxx. (x means a digit)

    You may also assume each line in the text file must not contain leading or trailing white spaces.

    For example, assume that file.txt has the following content:

    987-123-4567
    123 456 7890
    (123) 456-7890
    

    Your script should output the following valid phone numbers:

    987-123-4567
    (123) 456-7890

    关键的地方在于使用正则表达式组匹配行首,注意只有ERE才支持正则表达式组,awk默认是ERE,grep 中使用参数-E指定ERE,sed使用-r指定ERE

    # Read from the file file.txt and output all valid phone numbers to stdout.
    #grep -E '^(([0-9]{3}) |[0-9]{3}-)[0-9]{3}-[0-9]{4}$' file.txt
    #awk '/^(([0-9]{3}) |[0-9]{3}-)[0-9]{3}-[0-9]{4}$/' file.txt
    sed -r -n '/^(([0-9]{3}) |[0-9]{3}-)[0-9]{3}-[0-9]{4}$/p' file.txt
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  • 原文地址:https://www.cnblogs.com/chybot/p/4486152.html
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