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Removing line breaks from a shell variable

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# 1  
Old 09-12-2006
Removing line breaks from a shell variable
Here is my snippet of code...

Code:
getDescription()
{
        DESCRIPTION=$(dbaccess dncsdb - << !  2>/dev/null|sed -e 's/hctt_description//' -e '/^$/ d'|tr -d '\r'
select hct_type.hctt_description
from hct_type,hct_profile
where hct_type.hctt_id=hct_profile.hctt_id
and hct_type.hctt_revision=hct_profile.hctt_revision
and hct_profile.hct_mac_address="${1}";
! )
        printf "  %s\n" ${DESCRIPTION:-"## No DESCRIPTION ##"}
}

Here is the data contain in that column/table...

Code:
$ dbaccess dncsdb - << !
> select hctt_description from hct_type;
> !

Database selected.




hctt_description  Explorer 2010  Rev 2.0

hctt_description  Explorer 2000 Rev 2.0

hctt_description  Explorer 2000 version 3.5

hctt_description  Explorer 2000 version 3.7

...
...

72 row(s) retrieved.

Database closed.

The problem is when I print out the "DESCRIPTION" variable in the first segment, it displays with linebreaks in each white space, as such:

Code:
  Explorer
  8300
  version
  1.2

Smilie

How do I reformat the variable so the output looks like this?

Code:
  Explorer 8300 version 1.2

Thanks.
# 2  
Old 09-12-2006
Code:
echo ${DESCRIPTION:-"## No DESCRIPTION ##"} | tr '\n' ' '

# 3  
Old 09-12-2006
Quote:
Originally Posted by anbu23
Code:
echo ${DESCRIPTION:-"## No DESCRIPTION ##"} | tr '\n' ' '

That works.


BUT...


If I do this:

Code:
DESCRIPTION=`echo ${DESCRIPTION:-"## No DESCRIPTION ##"} | tr '\n' ' '`
printf " %s\n" ${DESCRIPTION}

I get this (actual output from my script):


Code:
00:0F:21:61:68:06
  Explorer
  8300
  version
  1.2

00:14:F8:BA:56:84
  Explorer
  8300
  version
  2.0

00:0F:21:61:6A:F6
  Explorer
  8300
  version
  1.2

00:0A:73:3C:4B:90
  ##
  No
  DESCRIPTION
  ##

Interesting.

Now I suspected that perhaps the '\n' in my "printf" statement may be the culprit. Sure enough, I made the following change:

Code:
        DESCRIPTION=`echo ${DESCRIPTION:-"## No DESCRIPTION ##"}|tr '\n' ' '`
        printf "  %s" ${DESCRIPTION}

and got the following output...

Code:
00:0F:21:61:68:06
  Explorer  8300  version  1.2
00:14:F8:BA:56:84
  Explorer  8300  version  2.0
00:0F:21:61:6A:F6
  Explorer  8300  version  1.2
00:0A:73:3C:4B:90
  ##  No  DESCRIPTION  ##

So I removed it from my original line which now looks like this and tried it. Got same output as above...

Code:
 printf "  %s" ${DESCRIPTION:-"## No DESCRIPTION ##"}

So the "final fix" is...

Code:
        printf "  %s" ${DESCRIPTION:-"## No DESCRIPTION ##"}
        printf "\n"

Which give this output:

Code:
00:0F:21:61:68:06
  Explorer  8300  version  1.2

00:14:F8:BA:56:84
  Explorer  8300  version  2.0

00:0F:21:61:6A:F6
  Explorer  8300  version  1.2

00:0A:73:3C:4B:90
  ## No DESCRIPTION ##

# 4  
Old 09-12-2006
But there is one more thing...

My string has two whitespaces between each word instead of one. How did that happen? And more importantly, how do I remove the extra whitespace?

Thanks.
# 5  
Old 09-12-2006
to remove extra spaces
Quote:
tr -s ' '
# 6  
Old 09-12-2006
I discovered the "printf" statement affects how variables are displayed depending how the variable is referenced...

Code:
X="A short sentence"

Code:
print $X

A short sentence

Code:
printf "%s" $X

Ashortsentence

Code:
printf " %s" $X

 A short sentence

Code:
printf "  %s" $X

  A  short  sentence

Code:
printf "%s\n" $X

A
short
sentence

Code:
printf " %s\n" $X

 A
 short
 sentence

And finally, to get it working correctly...

Code:
printf "  %s\n" "$X"

  A short sentence

Gotta have quotes around the variable reference.
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