replacing multiple lines with single line

Shell Programming and Scripting
1

Can any one give me the idea on replacing multiple blank lines with a single blank line?

Please conside it for a file having more than 100 number of characters.

Regards,
Siba

2

If you have that option with cat:

cat -s

With sed:

sed '/./,/^$/!d'
3

In my machine cat -s do nothing. The output is same as simply cat.

Te second one is doing fine in linux machine but not in HP-UX (When the no of characters in the line is more, say 1000 ).

4

I don't have a HP-UX box to test but try any of the following:

 # delete all CONSECUTIVE blank lines from file except the first; also
 # deletes all blank lines from top and end of file (emulates "cat -s")
 sed '/./,/^$/!d'          # method 1, allows 0 blanks at top, 1 at EOF
 sed '/^$/N;/\n$/D'        # method 2, allows 1 blank at top, 0 at EOF

 # delete all CONSECUTIVE blank lines from file except the first 2:
 sed '/^$/N;/\n$/N;//D'