Sorting blocks of lines

sorttext processing

I have a file that contains 4n lines. Here is an excerpt from it containing 8 lines

6115 8.88443
6116 6.61875
6118 16.5949
6117 19.4129
6116 6.619 
6117 16.5979 
6118 19.4111
6115 8.88433

What I want to do is sort a block, where each block consists of 4 lines based on the first column. The output for the excerpt should look as shown below.

6115 8.88443
6116 6.61875
6117 19.4129
6118 16.5949
6115 8.88433 
6116 6.619 
6117 16.5979 
6118 19.4111

Best Answer

One options is to use awk to add an initial serial number prefix every N lines (N=4 in your case). Then feed the prefix as the primary sorting column into sort.

Example with N=4:

awk '{print int((NR-1)/4), $0}' file.txt | sort -n -k1,1 -k2,2 | cut -f2- -d' '

Related Solutions

Sort a file based on length of the column/row

You can first add another column with count of characters with awk, do sort and then strip added column:

awk '{printf "%d %s\n", length($1), $0}' file.txt | sort -n -k1,1 | sed -E -e 's/^[0-9]+ //'

Sort unix alphabetically then numerically, not working as I intended

sort -k1,1 -nk2 is the same as sort -k1,1 -n -k2, same as sort -n -k1,1 -k2, as in the numerical sorting is turned on globally, for all the keys.

To sort the 2^nd key only numerically, you need to add n to that sort key description as in:

sort -k1,1 -k2n

Or:

sort -k1,1 -k2,2n

With n and with the default field separator 2 is the same as 2,2 though. 2 would be the part of the line starting from the second field, but when interpreted as a number, that's the same as the second field alone (2,2).

Here, you could also sort numerically on the number that is after chr and then alphabetically on the rest of the first field and then numerically on the second field with:

sort -k1.4n -k1,1 -k2n

Best Answer

Related Solutions

Sort a file based on length of the column/row

Sort unix alphabetically then numerically, not working as I intended

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