Linux 大文件如何切割与合并？

朴灿烈づ我的快乐病毒、 2022-09-01 00:55 153阅读 0赞

作者：Escape  
来源：[https://escapelife.github.io/posts/72f237d3.html][https_escapelife.github.io_posts_72f237d3.html]

**往往是因为网络传输的限制，导致很多时候，我们需要在 Linux 系统下进行大文件的切割。这样将一个大文件切割成为多个小文件，进行传输，传输完毕之后进行合并即可。**

*  Linux 大文件的分割与合并
 *  Linux 学习–文件分割与合并

![20210726192730651.png][]

**Linux下大文件切割与合并**

--------------------

## 1. 文件切割 - split ##

> **在 Linux 系统下使用 split 命令进行大文件切割很方便**

**\[1\] 命令语法**

# -a: 指定输出文件名的后缀长度(默认为2个:aa,ab...)
    # -d: 指定输出文件名的后缀用数字代替
    # -l: 行数分割模式(指定每多少行切成一个小文件;默认行数是1000行)
    # -b: 二进制分割模式(支持单位:k/m)
    # -C: 文件大小分割模式(切割时尽量维持每行的完整性)
    split [-a] [-d] [-l <行数>] [-b <字节>] [-C <字节>] [要切割的文件] [输出文件名]

**\[2\] 使用实例**

# 行切割文件
    $ split -l 300000 users.sql /data/users_
    
    # 使用数字后缀
    $ split -d -l 300000 users.sql /data/users_
    
    # 按字节大小分割
    $ split -d -b 100m users.sql /data/users_

**\[3\] 帮助信息**

# 帮助信息
    $ 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)            后缀名称的长度(默认为2)
          --additional-suffix=SUFFIX  append an additional SUFFIX to file names
      -b, --bytes=SIZE        put SIZE bytes per output file                       每个输出文件的字节大小
      -C, --line-bytes=SIZE   put at most SIZE bytes of records per output file    每个输出文件的最大字节大小
      -d                      use numeric suffixes starting at 0, not alphabetic   使用数字后缀代替字母后缀
          --numeric-suffixes[=FROM]  same as -d, but allow setting the start value
      -e, --elide-empty-files  do not generate empty output files with '-n'        不产生空的输出文件
          --filter=COMMAND    write to shell COMMAND; file name is $FILE           写入到shell命令行
      -l, --lines=NUMBER      put NUMBER lines/records per output file             设定每个输出文件的行数
      -n, --number=CHUNKS     generate CHUNKS output files; see explanation below  产生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/...'     无需缓存
          --verbose           print a diagnostic just before each                  显示分割进度
                                output file is opened
          --help     display this help and exit                                    显示帮助信息
          --version  output version information and exit                           显示版本信息
    
    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'

--------------------

## 2. 文件合并 - cat ##

> **在 Linux 系统下使用 cat 命令进行多个小文件的合并也很方便**

**\[1\] 命令语法**

# -n: 显示行号
    # -e: 以$字符作为每行的结尾
    # -t: 显示TAB字符(^I)
    cat [-n] [-e] [-t] [输出文件名]

**\[2\] 使用实例**

# 合并文件
    $ cat /data/users_* > users.sql

**\[3\] 帮助信息**

# 帮助信息
    $ 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
    
    Examples:
      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'

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[https_escapelife.github.io_posts_72f237d3.html]: https://escapelife.github.io/posts/72f237d3.html
[20210726192730651.png]: /images/20220829/3963b935fed34bba987e293bdcabf1e5.png
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[Mock _ Mock]: http://www.javastack.cn/article/2021/alibaba-testable-mock-released/
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