Shell Programming and Scripting

Greetings,

I've visited this forums for a long time and normally got an right answer but this time my problem doesn't seem to go away. What I'm trying to do is the following:

Code:

VAR="\n\nline1\nline2\nline3\nline4\nline5\nline6\nline7\n\n"

(The count of newlines is varying!)

If I echo this i get:

Code:

echo $VAR:

line1
line2
....
line7

/END

Now I want to Remove empty lines. Remember that the count of newlines is varying. I'm using the following sed command:

Code:

$VAR | sed '/^$/d'

When I echo this I get:

Code:

echo $VAR | sed '/^$/d':line1
line2
...
line7/END

However if I want to save it to $VAR something strange happens:
I use:

Code:

VAR=$(echo "$VAR" | sed '/^$/d')
echo $VAR:line1 line2 line3 line4 ... line7
echo "$VAR":line1
line2
...
line7/END

But as I'm cutting $VAR in a while loop

Code:

$VAR2=${VAR%%'\n'*}
$VAR=${VAR#*'\n'}

it doesn't seem to work. It doesn't recognize the newlines anymore and cuts away nothing. However, it cuts off in the right manner when I don't execute the sed-command, but I need to get rid of the empty newlines. I also tried changing the command to:

Code:

VAR="$(echo "$VAR" | sed '/^$/d')"
VAR="$(echo $VAR | sed '/^$/d')"

etc.
and many other versions but I can't seem to find the right answer.

Any help is highly appreciated.
Greetings,
Phil

Use CODE-tags when displaying code, data or logs to enhance readability, ty.

Hm I don't really see a curiousity - maybe I missed it or did not get what you want. Here is what I did, smiliar to yours:

Code:

$> VAR="\n\nline1\nline2\nline3\nline4\nline5\nline6\nline7\n\n"
$> echo -e $VAR


line1
line2
line3
line4
line5
line6
line7


$> echo -e $VAR| grep -v ^$
line1
line2
line3
line4
line5
line6
line7
$> NEU=`echo -e $VAR| grep -v ^$`
$> echo $NEU
line1 line2 line3 line4 line5 line6 line7
$> echo "$NEU"
line1
line2
line3
line4
line5
line6
line7

I don't understand what your goal is. If the desired output is echoing the variable with double quotes around it, that's just it?!

Hi zaxxon,
Thanks for trying to help me
In my script these line1,...,line7,... are the columns of different database tables, i just tried to make it simple
The problem is that I'm cutting away the different parts in a loop to get access to the single statements between the \n, e.g. i'm cutting away the back and as a result i get "line1" in the first iteration of the while loop and i cut the part out which i just selected (i cut out "line1\n" in the first iteration). I use these commands:

Code:

while [[ "$VAR" != "" ]]; do
   $VAR2=${VAR%%'\n'*}
   $VAR=${VAR#*'\n'}
done

but it doesn't seem to work with the sed-edited version. It doesn't recognize the newlines anymore and cuts away nothing. However, it cuts off in the right manner when I don't execute the sed-command and just execute the loop on the original $VAR, but I get all the empty lines of the variable and i really need to get rid of the empty newlines.

Greetings, Phil

I guess I am still not getting it - let's try to make it very simple. Just post an example input and an example of the desired output. I don't understand why you want to cut out newlines that are not there. That's where I am stuck. Also is it important you save all those strings to 1 variable and then work it again with a while loop? Maybe there is a simpler more clear way if you post the requested examples Let's give it a try.