Shell Programming and Scripting

Hi, I have a flat text file which contains blank line between each text line. Is there any command to get rid of it?

Thanks for your help

You can use awk:

Code:

awk '$1 !~ /(^$)/' someFile > someNewFile
mv someNewFile someFile

Or you can use sed:

Code:

sed '/^$/ d' someFile > someNewFile
mv someNewFile someFile

And here's a script copied from the man page for sed:

Code:

In this example, sed removes all blank lines (including those with just
<Tab> and <Space> characters) from padded_file:

   sed '
   /^$/ d
   /^[<Tab><Space>]*$/ d
   ' padded_file

Thanks a lot oombera. I tested it out, it works fine. I have another question, in the text file, if the first character in each line starts with "E", then get rid of the whole line.

Thanks

Thanks, I got the result I want. But I didn't quite understand what ^$ means.

You can use either of the first two scripts I posted .. just replace ^$ with ^E

To reply to the edit you made in your post, when using commands like sed and awk that search for patterns, there are special characters, such as ^ (which represents the beginning of a line) and $ (which represents the end of a line).

Basically, whereas ^E searches for any line with an E immediately following the beginning of the line, ^$ searches for any line whose end immediately follows its beginning (a blank line).

Thanks oombera, I learned a lot from you today.

You can use grep command also for the same
grep -v "^$" someFile > someNewFile

Regards,
Yeheya