delete first 100 lines from a file

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Operating Systems Solaris delete first 100 lines from a file
# 1  
Old 11-15-2007
Question delete first 100 lines from a file

I have a file with 28,00,000 lines of rows in this the first 80 lines will be chunks .

I want to delete the chunks of 80 lines. I tried tail -f2799920 filename.
is there any efficient way to do this.

Thanks in advance.
# 2  
Old 11-15-2007
sed '1,100d' filename > newfile

sed would be faster than tail in my opinion
# 3  
Old 11-15-2007
if -i option is available in sed ( GNU sed )

use it for in-place modification

sed -i '1,100d' filename

# 4  
Old 11-15-2007

Yes. Its really faster than the tail command.

Thanks Yogesh

# 5  
Old 06-09-2009
delete liines using sed.


I am trying to delete all lines in a file which starts with SG.

Command : sed -e "s/^SG/d/" bcpfile > test1.

But the above command just replaces 'SG' with 'd'. Please suggest the correct command to delete the whole line.

# 6  
Old 06-09-2009
sed -e "s/^SG//d"
# 7  
Old 06-09-2009
Originally Posted by a2156z
sed -e "s/^SG//d"
Should be:

sed "/^SG/d" file

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