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How to 'sed' the middle line?

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# 1  
Old 11-08-2006
How to 'sed' the middle line?
Hi,

If I have 90 lines and I want to print the 45th line, is there a quick sed command for this?

thx.
# 2  
Old 11-08-2006
sed2liners
Code:
# print line number 52
 sed -n '52p'                 # method 1
 sed '52!d'                   # method 2
 sed '52q;d'                  # method 3, efficient on large files

# 3  
Old 11-08-2006
Thanks, but would if I did not know the middle line number?

Is there a formula to figure out the middle line number?

Something like (wc -l) divided by 2 ?

thx.
# 4  
Old 11-08-2006
use this
echo `wc -l filename| cut -f 1 -d " "`/2 | bc
# 5  
Old 11-08-2006
echo `wc -l filename| cut -f 1 -d " "`/2 | bc
syntax error on line 1, teletype

Thanks for the replies, but I can't get it to work. The file is a list of names:

Frank
Sally
Sam
Julie
Joe
Jay
Ralph
John
Sally
Fred
Sue

word count(lines) is 11

I need to print the middle line which is 'Jay' which is the middle (6th) line.

thx.
# 6  
Old 11-08-2006
Don't know which would be faster, but..
Code:
# cat names
Frank
Sally
Sam
Julie
Joe
Jay
Ralph
John
Sally
Fred
Sue
# awk '{ lines[NR]=$0; } END { print lines[int(NR/2)+1] }' names
Jay
#

seems to do it.
# 7  
Old 11-08-2006
Code:
half=$(( $( wc -l < myFile.txt) / 2 )); echo $half

.... the rest can be done with the original post.
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