truncate half of `input.txt`

dd of=output.txt if=input.txt ibs=1 skip=$(expr `stat -c%s input.txt` / 2)

By: kev
2011-07-10 12:04:48

What Others Think

Examples, man :-) Interesting. So, it skips the first half of the file, leaving you with the end. "Truncate" usually implies the opposite! I can see that being useful for long log files. What do you use it for?
flatcap · 473 weeks and 6 days ago
head -n $(( $(wc -l $file)/2 )) $file tail -----------------//-------------------
RanyAlbeg · 473 weeks and 6 days ago
@RanyAlbeg: I thought about head/tail myself, but it would be pretty inefficient for very long files. The original, though it will probably split a line, will be very fast.
flatcap · 473 weeks and 6 days ago
Then u can use sed read l _ <<< "$(wc -l foo.txt)"; sed -n "1,$((l/2))"p foo.txt
RanyAlbeg · 473 weeks and 5 days ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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