如何在 Linux下进行文件切割操作？

在 Linux 系统下使用 split 命令进行大文件切割很方便

#?-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]

#?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'

在 Linux 系统下使用 cat 命令进行多个小文件的合并也很方便

#?-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]

#?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) cat invocation'

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