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。
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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
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]
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_
帮助信息
# 帮助信息$ split --helpusage: 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 $file 写入到shell命令行 -l, --lines=number put number lines/records per output file 设定每个输出文件的行数 -n, --number=chunks generate chunks output files; see explanation below 产生chunks文件 -t, --separator=sep use sep instead of newline as the record separator; 使用新字符分割 '\0' (zero) specifies the nul character -u, --unbuffered immediately copy input to output with '-n r/...' 无需缓存 --verbose print a diagnostic just before each 显示分割进度 output file is opened --help display this help and exit 显示帮助信息 --version output version information and exit 显示版本信息the size argument is an integer and optional unit (example: 10k is 10*1024).units are k,m,g,t,p,e,z,y (powers of 1024) or kb,mb,... (powers of 1000).chunks may be: n split into n files based on size of input k/n output kth of n to stdout l/n split into n files without splitting lines/records l/k/n output kth of n to stdout without splitting lines/records r/n like 'l' but use round robin distribution r/k/n likewise but only output kth of n to stdoutgnu coreutils online help: <http://www.gnu.org/software/coreutils/>full documentation at: <http://www.gnu.org/software/coreutils/split>or available locally via: info '(coreutils) split invocation'
文件合并 - cat
在 linux 系统下使用 cat 命令进行多个小文件的合并也很方便
命令语法
-n: #显示行号
-e: #以$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]
使用实例
# 合并文件$ cat /data/users_* > users.sql
帮助信息
# 帮助信息$ cat --husage: 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 exitexamples: 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)
以上就是在linux系统下进行大文件的切割和合并的详细内容。