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导读 | 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。 |
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' |
3. 参考文档
- Linux 大文件的分割与合并
- Linux 学习–文件分割与合并
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