topic Re: need to add trailing spaces to match fixed character length in Operating System - Linux

need to add trailing spaces to match fixed character length

sathis kumar — Fri, 04 Apr 2008 13:30:02 GMT

Hello,

My i/p file (INPUT) has 2 lines. First line has 41 chars and the second one has 100 chars.
I need to have fixed character length (145) in the all the lines of that file. I tried the below script but unable to pass the varaible 'j' in the for loop.

i=0;
while read line
do
count=`echo $line | wc -c`
j=`expr 145 - $count`
echo "Char count is $count \n"
echo $line | awk '{ printf $1
for (k=0; k<$j; k++) printf " " } ' >> OUTPUT
done < INPUT

NOTE : error comes due to "k<$j" used ...

Can anybody please help me in this?

Thanks & Regards,
Sathis Kumar.B

Re: need to add trailing spaces to match fixed character length

Steven Schweda — Fri, 04 Apr 2008 13:48:02 GMT

I only know simple-minded, crude ways to do
such things.

td176> str='abc'

td176> echo ">${str}<"
>abc<

td176> strp=` echo " $str" | sed -e 's/.*$......$$/\1/' `

td176> echo ">${strp}<"
> abc<

But I have fun.

Re: need to add trailing spaces to match fixed character length

Mounaam — Fri, 04 Apr 2008 14:07:45 GMT

Hi,

example with Posix shell:
$ typeset -R8 a=123
$ typeset -L8 b=123
Result:
$ echo "|$a|\n|$b|"
| 123|
|123 |

For your case:
$ typeset -L145 l
$ while read l;do echo $l;done < input > output

Re: need to add trailing spaces to match fixed character length

Hein van den Heuvel — Fri, 04 Apr 2008 14:26:05 GMT

Just use awk or perl or printf in the loop.

$IFS=""
$while read line
do
printf "%-145s\n" $line
done < INPUT

or

$ awk '{printf("%-80s\n",$0)}' INPUT > OUTPUT

or by adding a piece of string in perl:

$ perl -pe '$pad=q( )x(145-length); s/$/$pad/e' INPUT > OUTPUT

so many ways....

All so much better than printing a character at a time until done.

hth.
Hein.

Re: need to add trailing spaces to match fixed character length

Peter Nikitka — Sat, 05 Apr 2008 06:19:25 GMT

Hi,

leaving the best solution of Mounaam beside, your mistake is the mixing of a shell variable $j into awk, which is not possible in the way you did it.
1) Splice up the command string the shell parses
... | awk '{ printf $1
for (k=0; k<'$j'; k++) printf " " } ' ...
2) Supply an awk variable
... | awk -v j=$j '{ printf $1
for (k=0; k
There are other constructs in you awk which make your solution break:
1) Dealing just with the printf() function without '\n' in the strings will result in one long line.
2) Having spaces in your line, only a part of the input will be copied.

If this awk is part of a larger processing, I suggest this approach:
awk '{printf($0);for(k=length($0);k<145;k++) printf(" ");printf("\n")}' input >output

mfG Peter