Linux

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

  1. # -a: 指定输出文件名的后缀长度(默认为2个:aa,ab...)
  2. # -d: 指定输出文件名的后缀用数字代替
  3. # -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)
  4. # -b: 二进制分割模式(支持单位:k/m)
  5. # -C: 文件大小分割模式(切割时尽量维持每行的完整性)
  6. 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

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

3、帮助信息

  1. # 帮助信息
  2. $ split --help
  3. Usage: split [OPTION]... [FILE [PREFIX]]
  4. Output pieces of FILE to PREFIXaa, PREFIXab, ...;
  5. default size is 1000 lines, and default PREFIX is 'x'.
  7. With no FILE, or when FILE is -, read standard input.
  9. Mandatory arguments to long options are mandatory for short options too.
  10.   -a, --suffix-length=N   generate suffixes of length N (default 2)            后缀名称的长度(默认为2)
  11.       --additional-suffix=SUFFIX  append an additional SUFFIX to file names
  12.   -b, --bytes=SIZE        put SIZE bytes per output file                       每个输出文件的字节大小
  13.   -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
  14.   -d                      use numeric suffixes starting at 0, not alphabetic   使用数字后缀代替字母后缀
  15.       --numeric-suffixes[=FROM]  same as -d, but allow setting the start value
  16.   -e, --elide-empty-files  do not generate empty output files with '-n'        不产生空的输出文件
  17.       --filter=COMMAND    write to shell COMMAND; file name is $FILE           写入到shell命令行
  18.   -l, --lines=NUMBER      put NUMBER lines/records per output file             设定每个输出文件的行数
  19.   -n, --number=CHUNKS     generate CHUNKS output files; see explanation below  产生chunks文件
  20.   -t, --separator=SEP     use SEP instead of newline as the record separator;  使用新字符分割
  21.                             '\0' (zero) specifies the NUL character
  22.   -u, --unbuffered        immediately copy input to output with '-n r/...'     无需缓存
  23.       --verbose           print a diagnostic just before each                  显示分割进度
  24.                             output file is opened
  25.       --help     display this help and exit                                    显示帮助信息
  26.       --version  output version information and exit                           显示版本信息
  28. The SIZE argument is an integer and optional unit (example: 10K is 10*1024).
  29. Units are K,M,G,T,P,E,Z,Y (powers of 1024) or KB,MB,... (powers of 1000).
  31. CHUNKS may be:
  32.   N       split into N files based on size of input
  33.   K/N     output Kth of N to stdout
  34.   l/N     split into N files without splitting lines/records
  35.   l/K/N   output Kth of N to stdout without splitting lines/records
  36.   r/N     like 'l' but use round robin distribution
  37.   r/K/N   likewise but only output Kth of N to stdout
  39. GNU coreutils online help: <http://www.gnu.org/software/coreutils/>
  40. Full documentation at: <http://www.gnu.org/software/coreutils/split>
  41. 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

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

2、使用实例

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

3、帮助信息

  1. # 帮助信息
  2. $ cat --h
  3. Usage: cat [OPTION]... [FILE]...
  4. Concatenate FILE(s) to standard output.
  6. With no FILE, or when FILE is -, read standard input.
  8. -A, --show-all           equivalent to -vET
  9. -b, --number-nonblank    number nonempty output lines, overrides -n
  10. -e                       equivalent to -vE
  11. -E, --show-ends          display $ at end of each line
  12. -n, --number             number all output lines
  13. -s, --squeeze-blank      suppress repeated empty output lines
  14. -t                       equivalent to -vT
  15. -T, --show-tabs          display TAB characters as ^I
  16. -u                       (ignored)
  17. -v, --show-nonprinting   use ^ and M- notation, except for LFD and TAB
  18. --help     display this help and exit
  19. --version  output version information and exit
  21. Examples:
  22. cat f - g  Output f's contents, then standard input, then g's contents.
  23. cat        Copy standard input to standard output.
  25. GNU coreutils online help: <http://www.gnu.org/software/coreutils/>
  26. Full documentation at: <http://www.gnu.org/software/coreutils/cat>
  27. or available locally via: info '(coreutils) cat invocation'