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      首頁 運維干貨Linux 下大文件切割與合并

      Linux 下大文件切割與合并


      往往是因為網絡傳輸的限制,導致很多時候,我們需要在 Linux 系統下進行大文件的切割。這樣將一個大文件切割成為多個小文件,進行傳輸,傳輸完畢之后進行合并即可。

      Linux 下大文件切割與合并插圖

      文件切割 – split

      在 Linux 系統下使用 split 命令進行大文件切割很方便


      -a: #指定輸出文件名的后綴長度(默認為2個:aa,ab...)
      -d: #指定輸出文件名的后綴用數字代替
      -l: #行數分割模式(指定每多少行切成一個小文件;默認行數是1000行)
      -b: #二進制分割模式(支持單位:k/m)
      -C: #文件大小分割模式(切割時盡量維持每行的完整性)
      split [-a] [-d] [-l <行數>] [-b <字節>] [-C <字節>] [要切割的文件] [輸出文件名]


      # 行切割文件
      $ split -l 300000 users.sql /data/users_
      # 使用數字后綴
      $ split -d -l 300000 users.sql /data/users_
      # 按字節大小分割
      $ split -d -b 100m users.sql /data/users_
      # 幫助信息
      $ split --help
      Usage: split [OPTION]... [FILE [PREFIX]]
      Output pieces of FILE to PREFIXaa, PREFIXab, ...;
      default size is 1000 lines, and default PREFIX is 'x'.
      With no FILE, or when FILE is -, read standard input.
      Mandatory arguments to long options are mandatory for short options too.
        -a, --suffix-length=N   generate suffixes of length N (default 2)            后綴名稱的長度(默認為2)
            --additional-suffix=SUFFIX  append an additional SUFFIX to file names
        -b, --bytes=SIZE        put SIZE bytes per output file                       每個輸出文件的字節大小
        -C, --line-bytes=SIZE   put at most SIZE bytes of records per output file    每個輸出文件的最大字節大小
        -d                      use numeric suffixes starting at 0, not alphabetic   使用數字后綴代替字母后綴
            --numeric-suffixes[=FROM]  same as -d, but allow setting the start value
        -e, --elide-empty-files  do not generate empty output files with '-n'        不產生空的輸出文件
            --filter=COMMAND    write to shell COMMAND; file name is $FILE           寫入到shell命令行
        -l, --lines=NUMBER      put NUMBER lines/records per output file             設定每個輸出文件的行數
        -n, --number=CHUNKS     generate CHUNKS output files; see explanation below  產生chunks文件
        -t, --separator=SEP     use SEP instead of newline as the record separator;  使用新字符分割
                                  '\0' (zero) specifies the NUL character
        -u, --unbuffered        immediately copy input to output with '-n r/...'     無需緩存
            --verbose           print a diagnostic just before each                  顯示分割進度
                                  output file is opened
            --help     display this help and exit                                    顯示幫助信息
            --version  output version information and exit                           顯示版本信息
      The SIZE argument is an integer and optional unit (example: 10K is 10*1024).
      Units are K,M,G,T,P,E,Z,Y (powers of 1024) or KB,MB,... (powers of 1000).
      CHUNKS may be:
        N       split into N files based on size of input
        K/N     output Kth of N to stdout
        l/N     split into N files without splitting lines/records
        l/K/N   output Kth of N to stdout without splitting lines/records
        r/N     like 'l' but use round robin distribution
        r/K/N   likewise but only output Kth of N to stdout
      GNU coreutils online help: <http://www.gnu.org/software/coreutils/>
      Full documentation at: <http://www.gnu.org/software/coreutils/split>
      or available locally via: info '(coreutils) split invocation'

      文件合并 – cat

      在 Linux 系統下使用 cat 命令進行多個小文件的合并也很方便


      -n: #顯示行號
      -e: #以$字符作為每行的結尾
      -t: #顯示TAB字符(^I)
      cat [-n] [-e] [-t] [輸出文件名]


      # 合并文件
      $ cat /data/users_* > users.sql
      # 幫助信息
      $ cat --h
      Usage: cat [OPTION]... [FILE]...
      Concatenate FILE(s) to standard output.
      With no FILE, or when FILE is -, read standard input.
        -A, --show-all           equivalent to -vET
        -b, --number-nonblank    number nonempty output lines, overrides -n
        -e                       equivalent to -vE
        -E, --show-ends          display $ at end of each line
        -n, --number             number all output lines
        -s, --squeeze-blank      suppress repeated empty output lines
        -t                       equivalent to -vT
        -T, --show-tabs          display TAB characters as ^I
        -u                       (ignored)
        -v, --show-nonprinting   use ^ and M- notation, except for LFD and TAB
            --help     display this help and exit
            --version  output version information and exit
        cat f - g  Output f's contents, then standard input, then g's contents.
        cat        Copy standard input to standard output.
      GNU coreutils online help: <http://www.gnu.org/software/coreutils/>
      Full documentation at: <http://www.gnu.org/software/coreutils/cat>
      or available locally via: info '(coreutils) cat invocation'

      作者: Escape
      鏈接: https://escapelife.github.io/posts/72f237d3.html







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