I need to extract a set number of lines from a file given the start line number and end line number.
How could I quickly do this under unix (it's actually Solaris so gnu flavour isn't available).
Thx
4 Answers
To print lines 6-10:
sed -n '6,10p' file
If the file is huge, and the end line number is small compared to the number of lines, you can make it more efficient by:
sed -n '10q;6,10p' file
From testing a file with a fairly large number of lines:
$ wc -l test.txt
368048 test.txt
$ du -k test.txt
24640 test.txt
$ time sed -n '10q;6,10p' test.txt >/dev/null
real 0m0.005s
user 0m0.001s
sys 0m0.003s
$ time sed -n '6,10p' test.txt >/dev/null
real 0m0.123s
user 0m0.092s
sys 0m0.030s
you can do it with nawk as well
#!/bin/sh
start=10
end=20
nawk -vs="$start" -ve="$end" 'NR>e{exit}NR>=s' file
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