How do I break a large, +4GB file into smaller files of about 500MB each.
And how do I re-assemble them again to get the original file?
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2text line-wise version: stackoverflow.com/questions/2016894/…– Ciro Santilli OurBigBook.comApr 26, 2016 at 12:22
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Related: How to split larger files into smaller parts?– kenorbOct 22, 2017 at 13:40
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2 Answers
You can use split and cat.
For example something like
$ split --bytes 500M --numeric-suffixes --suffix-length=3 foo foo.
(where the input filename is foo and the last argument is the output prefix). This will create files like foo.000 foo.001 ...
The same command with short options:
$ split -b 100k -d -a 3 foo foo
You can also specify "--line-bytes" if you wish it to split on line boundaries instead of just exact number of bytes.
For re-assembling the generated pieces again you can use e.g.:
$ cat foo.* > foo_2
(assuming that the shell sorts the results of shell globbing - and the number of parts does not exceed the system dependent limit of arguments)
You can compare the result via:
$ cmp foo foo_2
$ echo $?
(which should output 0)
Alternatively, you can use a combination of find/sort/xargs to re-assemble the pieces:
$ find -maxdepth 1 -type f -name 'foo.*' | sort | xargs cat > foo_3
answered Sep 4, 2010 at 19:00
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6When assembling, I recommend
cat foo.{000..NNN}whereNNNis the last expected piece. That way you get an error message if one of the pieces is missing. But note that-dto get numeric suffixes is specific to GNU split; on other platforms you have to make do withfoo.aaa,foo.aab, etc. Oct 17, 2010 at 11:16 -
2And bear in mind that, for
split, KB = 1000, K = 1024, MB = 1000*1000, M = 1024*1024 etc.– ZorawarNov 29, 2012 at 18:05 -
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1If you decide to ease pain by using a utility.
rarand7zipare often used in making such splits easier to reassemble cross-platform– infixedJun 3, 2016 at 18:05
You can also do this with Archive Manager if you prefer a GUI. Look under 'Save->Other Options->Split into volumes of'.
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