在Linux系统下进行大文件的切割和合并

split [-a] [-d] [-l <行数>] [-b <字节>] [-C <字节>] [要切割的文件] [输出文件名]

# 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_

# 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'

cat [-n] [-e] [-t] [输出文件名]

# 合并文件

$ cat /data/users_* > users.sql

# 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)