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Divide large data files into smaller files

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Top Forums Shell Programming and Scripting Divide large data files into smaller files
# 8  
Old 07-21-2010
Another approch with awk.
In the following script (ad23.sh) bigfile is the input file to split (ad23.txt) and maxsize is the maximum size (in bytes) of the fragments (ad23.txt_*).
Code:
bigfile=./ad23.txt
maxsize=${1:-200}

rm ${bigfile}_* >/dev/null 2>&1

awk -v msize=${maxsize} '

function print_record() {
   if ( rsize == 0 ) return;
   if ( csize+rsize > msize && csize != 0 || ifile == 0 ) {
      outfile = FILENAME "_" ++ifile;
      csize = 0;
   }
   csize += rsize;
   print record > outfile;
}

/^>[0-9]+$/ {
   print_record();
   record = $0;
   rsize  = length+1;
   next;
}

{
   record = (record ? record "\n" : "") $0;
   rsize  += length+1;
}

END {
   print_record();
}

' ${bigfile}

Input file (ad23.txt 873 bytes):
Code:
>0001
1 aaaaaaaaaaaaaaaaaaaaaaaaaaaa
1 bbbbbbbbbbbbbbbbbbbbbbbbbbbb
1 cccccccccccccccccccccccccccc
1 dddddddddddddddddddddddddddd
1 eeeeeeeeeeeeeeeeeeeeeeeeeeee
>0002
2 aaaaaaaaaaaaaaaaaaaaaaaaaaaa
2 bbbbbbbbbbbbbbbbbbbbbbbbbbbb
>0003
3 aaaaaaaaaaaaaaaaaaaaaaaaaaaa
3 bbbbbbbbbbbbbbbbbbbbbbbbbbbb
3 cccccccccccccccccccccccccccc
3 dddddddddddddddddddddddddddd
3 eeeeeeeeeeeeeeeeeeeeeeeeeeee
3 ffffffffffffffffffffffffffff
3 gggggggggggggggggggggggggggg
>0004
4 aaaaaaaaaaaaaaaaaaaaaaaaaaaa
>0005
5 aaaaaaaaaaaaaaaaaaaaaaaaaaaa
5 bbbbbbbbbbbbbbbbbbbbbbbbbbbb
5 cccccccccccccccccccccccccccc
5 dddddddddddddddddddddddddddd
5 eeeeeeeeeeeeeeeeeeeeeeeeeeee
5 ffffffffffffffffffffffffffff
5 gggggggggggggggggggggggggggg
5 hhhhhhhhhhhhhhhhhhhhhhhhhhhh
5 iiiiiiiiiiiiiiiiiiiiiiiiiiii
5 jjjjjjjjjjjjjjjjjjjjjjjjjjjj
>0006
6 aaaaaaaaaaaaaaaaaaaaaaaaaaaa
6 aaaaaaaaaaaaaaaaaaaaaaaaaaaa

Execution with maxsize=300
Code:
$ ./ad23.sh 300
$ wc -c ad23.txt_*
229 ad23.txt_1
260 ad23.txt_2
316 ad23.txt_3
 68 ad23.txt_4
873 total
$ more -999 ad23.txt_*
::::::::::::::
ad23.txt_1
::::::::::::::
>0001
1 aaaaaaaaaaaaaaaaaaaaaaaaaaaa
1 bbbbbbbbbbbbbbbbbbbbbbbbbbbb
1 cccccccccccccccccccccccccccc
1 dddddddddddddddddddddddddddd
1 eeeeeeeeeeeeeeeeeeeeeeeeeeee
>0002
2 aaaaaaaaaaaaaaaaaaaaaaaaaaaa
2 bbbbbbbbbbbbbbbbbbbbbbbbbbbb
::::::::::::::
ad23.txt_2
::::::::::::::
>0003
3 aaaaaaaaaaaaaaaaaaaaaaaaaaaa
3 bbbbbbbbbbbbbbbbbbbbbbbbbbbb
3 cccccccccccccccccccccccccccc
3 dddddddddddddddddddddddddddd
3 eeeeeeeeeeeeeeeeeeeeeeeeeeee
3 ffffffffffffffffffffffffffff
3 gggggggggggggggggggggggggggg
>0004
4 aaaaaaaaaaaaaaaaaaaaaaaaaaaa
::::::::::::::
ad23.txt_3
::::::::::::::
>0005
5 aaaaaaaaaaaaaaaaaaaaaaaaaaaa
5 bbbbbbbbbbbbbbbbbbbbbbbbbbbb
5 cccccccccccccccccccccccccccc
5 dddddddddddddddddddddddddddd
5 eeeeeeeeeeeeeeeeeeeeeeeeeeee
5 ffffffffffffffffffffffffffff
5 gggggggggggggggggggggggggggg
5 hhhhhhhhhhhhhhhhhhhhhhhhhhhh
5 iiiiiiiiiiiiiiiiiiiiiiiiiiii
5 jjjjjjjjjjjjjjjjjjjjjjjjjjjj
::::::::::::::
ad23.txt_4
::::::::::::::
>0006
6 aaaaaaaaaaaaaaaaaaaaaaaaaaaa
6 aaaaaaaaaaaaaaaaaaaaaaaaaaaa
$

Another execution with maxsize=500
Code:
$ ./ad23.sh 500
$ wc -c ad23.txt_*
489 ad23.txt_1
384 ad23.txt_2
873 total
$ more -999 ad23.txt_*
::::::::::::::
ad23.txt_1
::::::::::::::
>0001
1 aaaaaaaaaaaaaaaaaaaaaaaaaaaa
1 bbbbbbbbbbbbbbbbbbbbbbbbbbbb
1 cccccccccccccccccccccccccccc
1 dddddddddddddddddddddddddddd
1 eeeeeeeeeeeeeeeeeeeeeeeeeeee
>0002
2 aaaaaaaaaaaaaaaaaaaaaaaaaaaa
2 bbbbbbbbbbbbbbbbbbbbbbbbbbbb
>0003
3 aaaaaaaaaaaaaaaaaaaaaaaaaaaa
3 bbbbbbbbbbbbbbbbbbbbbbbbbbbb
3 cccccccccccccccccccccccccccc
3 dddddddddddddddddddddddddddd
3 eeeeeeeeeeeeeeeeeeeeeeeeeeee
3 ffffffffffffffffffffffffffff
3 gggggggggggggggggggggggggggg
>0004
4 aaaaaaaaaaaaaaaaaaaaaaaaaaaa
::::::::::::::
ad23.txt_2
::::::::::::::
>0005
5 aaaaaaaaaaaaaaaaaaaaaaaaaaaa
5 bbbbbbbbbbbbbbbbbbbbbbbbbbbb
5 cccccccccccccccccccccccccccc
5 dddddddddddddddddddddddddddd
5 eeeeeeeeeeeeeeeeeeeeeeeeeeee
5 ffffffffffffffffffffffffffff
5 gggggggggggggggggggggggggggg
5 hhhhhhhhhhhhhhhhhhhhhhhhhhhh
5 iiiiiiiiiiiiiiiiiiiiiiiiiiii
5 jjjjjjjjjjjjjjjjjjjjjjjjjjjj
>0006
6 aaaaaaaaaaaaaaaaaaaaaaaaaaaa
6 aaaaaaaaaaaaaaaaaaaaaaaaaaaa
$

Jean-Pierre.
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