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To print a specific line from a file

Terminal - To print a specific line from a file
awk 'FNR==5' <file>
2009-10-20 22:52:41
User: dennisw
Functions: awk
1
To print a specific line from a file

Just one character longer than the sed version ('FNR==5' versus -n 5p). On my system, without using "exit" or "q", the awk version is over four times faster on a ~900K file using the following timing comparison:

testfile="testfile"; for cmd in "awk 'FNR==20'" "sed -n '20p'"; do echo; echo $cmd; eval "$cmd $testfile"; for i in {1..3}; do time for j in {1..100}; do eval "$cmd $testfile" >/dev/null; done; done; done

Adding "exit" or "q" made the difference between awk and sed negligible and produced a four-fold improvement over the awk timing without the "exit".

For long files, an exit can speed things up:

awk 'FNR==5{print;exit}' <file>

Alternatives

There are 3 alternatives - vote for the best!

Terminal - Alternatives
sed -n 5p <file>
2009-10-15 11:00:48
User: Waldirio
Functions: sed
37

You can get one specific line during any procedure. Very interesting to be used when you know what line you want.

awk '{if (NR == 3) print}' <file>
2009-10-19 15:58:09
User: yooreck
Functions: awk
-5

I don't know if it's better but works fine :)

tail -n +<N> <file> | head -n 1
2011-09-30 08:30:30
User: qweqq
Functions: head tail
-5

Tail is much faster than sed, awk because it doesn't check for regular expressions.

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