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while read dir ev file; do
    # do stuff
done

説明が見つからない部分がそのread dir ev部分です。私はBashに精通していません。私は主にPHPとMySQLを行っています。誰か説明できますか？

ありがとう。

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1 に答える 1

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短いバージョンでは、入力から一度に1行を取得し、そこから個々のフィールドを変数に割り当てます。

read dir ev file行を1つずつ読み取り、各行に3つの項目が含まれていることを期待します。次に、最初の項目を、という名前の変数に割り当て、dir2番目の項目をという名前の変数に割り当て、3番目の項目をという名前の変数に割り当てevますfile。

の出力からhelp read：

（編集：より読みやすいバージョンはこちら：http ：//ss64.com/bash/read.html ）

read: read [-ers] [-a array] [-d delim] [-i text] [-n nchars] [-N nchars] [-p prompt] [-t timeout] [-u fd] [name ...]
    Read a line from the standard input and split it into fields.

    Reads a single line from the standard input, or from file descriptor FD
    if the -u option is supplied.  The line is split into fields as with word
    splitting, and the first word is assigned to the first NAME, the second
    word to the second NAME, and so on, with any leftover words assigned to
    the last NAME.  Only the characters found in $IFS are recognized as word
    delimiters.

    If no NAMEs are supplied, the line read is stored in the REPLY variable.

    Options:
      -a array  assign the words read to sequential indices of the array
                variable ARRAY, starting at zero
      -d delim  continue until the first character of DELIM is read, rather
                than newline
      -e                use Readline to obtain the line in an interactive shell
      -i text   Use TEXT as the initial text for Readline
      -n nchars return after reading NCHARS characters rather than waiting
                for a newline, but honor a delimiter if fewer than NCHARS
                characters are read before the delimiter
      -N nchars return only after reading exactly NCHARS characters, unless
                EOF is encountered or read times out, ignoring any delimiter
      -p prompt output the string PROMPT without a trailing newline before
                attempting to read
      -r                do not allow backslashes to escape any characters
      -s                do not echo input coming from a terminal
      -t timeout        time out and return failure if a complete line of input is
                not read withint TIMEOUT seconds.  The value of the TMOUT
                variable is the default timeout.  TIMEOUT may be a
                fractional number.  If TIMEOUT is 0, read returns success only
                if input is available on the specified file descriptor.  The
                exit status is greater than 128 if the timeout is exceeded
      -u fd             read from file descriptor FD instead of the standard input

    Exit Status:
    The return code is zero, unless end-of-file is encountered, read times out,
    or an invalid file descriptor is supplied as the argument to -u.
于 2012-11-17T04:13:45.460 に答える