topic Re: Removing spaces between lines in Operating System - HP-UX

Removing spaces between lines

N Gopal — Thu, 10 Jan 2008 09:40:31 GMT

Hi All,

I am having one file say abc.txt. File has two fields.Entries of files :

Prefix description

"202xxxx" This is hhhhh tatat.

"303nnnnn" This is 2nd line.

"606hhhh" This is 3rd line.
......
.... and so on.

Between two lines many blank lines are there. I want to remove all blank line.
Logic i have written is:

Code:
****************************************
var1=`wc -l abc.txt.txt | cut -f1 -d' '`

#This will take total no of lines in file.

count=1
while read line
do

length=`echo $line | wc -w`
if [ $length -eq 0 ]; then
echo " NULL LINE "
else
`echo $line >> abc_final.txt`
fi;
if [ $count -eq $var ]; then
echo " Breaking loop "
break;
fi;
count=`expr $count + 1`
done < abc.txt

******************************************
Can some one suggest any simple and effective way to acieve this?

Thanks

Re: Removing spaces between lines

Richard Hepworth — Thu, 10 Jan 2008 10:01:22 GMT

Hi,

You can use awk to achieve this:

cat abc.txt | awk '$0!~/^$/ {print $0}' > abc.txt.new

regards,

Richard

Re: Removing spaces between lines

Oviwan — Thu, 10 Jan 2008 10:06:00 GMT

Hey

Check this from http://sed.sourceforge.net/sed1line.txt:

# delete ALL blank lines from a file (same as "grep '.' ")
sed '/^$/d' # method 1
sed '/./!d' # method 2

example:
$sed '/./!d' yourfile >> newfile

Regards

Re: Removing spaces between lines

john korterman — Thu, 10 Jan 2008 10:07:23 GMT

Hi,

grep -v "^$" abc.txt >newfile

would also be possible.

regards,
John K.

Re: Removing spaces between lines

Srikanth Arunachalam — Thu, 10 Jan 2008 11:21:57 GMT

Hi Gopal,

Simply do sed '/^$/d' abc.txt > def.txt that should suffice.

where abc.txt will have quiet few new lines in it, like
abc

qasd

sd
EOF

def.txt will be
abc
qasd
sd
EOF

Thanks,
Srikanth

Re: Removing spaces between lines

James R. Ferguson — Thu, 10 Jan 2008 13:02:41 GMT

Hi:

The problem with reqular expressions like:

/^$/

...is that this assumes that a "blank" line consists only of a newline character without any intervening spaces and/or tabs.

If you wish to use 'sed':

# sed '/^[ ]*$/d' file

...where the expression in brackets consists of a space followed by a tab character, will work. Some 'sed' variations (but not HP's) allow a '\t' in lieu of typing the actual TAB.

Otherwise, I prefer:

# perl -ne 'print unless /^\s*$/' file

The '\s' represents "whitespace" which is defined to include both spaces and tabs. Hence if a line consists of zero or more characters of whitespace only, it is skipped.

Regards!

...JRF...

Re: Removing spaces between lines

Sandman! — Thu, 10 Jan 2008 20:13:16 GMT

Try the ex(1) construct below:

ex -s file <g/^$/d
x
EOF

Re: Removing spaces between lines

N Gopal — Fri, 11 Jan 2008 06:42:17 GMT

Hi All,

Appologies for very delay in responding.

Both solutions given by James is working for me. I am choosing perl out of that.

Thanks a lot to all for their replies.

Regards

Re: Removing spaces between lines

Dennis Handly — Fri, 11 Jan 2008 08:59:43 GMT

There is a command to do that: rmnl(1)

Re: Removing spaces between lines

Bill Hassell — Fri, 11 Jan 2008 12:24:32 GMT

The simplest way is to use ssp and rmnl (check the man pages). rmnl removes all blank lines except those at the front of the file. ssp removes the blanks lines at the front and then reduces all subsequent blank lines to just one. This will remove all your blank lines:

cat $MYFILE | ssp | rmnl >> abc_final.txt

Note that if the incoming file is badly formatted with space-filled lines (which look blank but actually have blank characters) then additional steps will be needed to remove those 'looks-blank' lines.