Shell Programming and Scripting

I have textfile (source.txt) with different length of lines in it. Can anybody help to compose a script under bash which would add suitable number of trailing spaces to the end of each line so that after the processing the each line would have the same (let's say 100 char) length? Output can be redirected to dest.txt file.
Thank a lot

Code:

awk '{printf("%100s\n", $0) }' oldfile > newfile

I tried this, but script produce output file which contains leading spaces (it aligns lines from source file to right). My need is to add spaces to end of each line (from source file).

---------- Post updated at 02:07 PM ---------- Previous update was at 02:04 PM ----------

Only a small mistake was there. This accomplish my needs:

Code:

awk '{printf("%-100s\n", $0) }' oldfile > newfile

Thanks a lot!

---------- Post updated at 02:27 PM ---------- Previous update was at 02:07 PM ----------

Can you still help to know how to concatenate these two commands? The first one finds out the length of longest line in the file. The second one adds trailing spaces to each line to have fixed line length equal 100 chars. I want to use the result of first script to specify length of the each line in the output file of second script (not to have it always 100 chars long):



1)

Code:

awk ' { if ( length > x ) { x = length } }END{ print x }' oldfile

2)

Code:

awk '{printf("%-100s\n", $0) }' oldfile > newfile

Code:

awk -v x=0 '(NR == FNR) { if(length > x) x = length;next } { printf("%-"x"s\n", $0) }' oldfile oldfile > newfile

Simple! - for those who know
Thank you very much!

I don't see how that accomplishes what you sought. The max length of a line is computed but not used for anything. printf is still using a hardcoded 100 character field width. Try the following:

Code:

awk '{l=length; if (l>x) x=l; a[NR]=$0} END {fstr="%-"x"s\n"; for(i=1;i<=NR;i++) printf(fstr, a[i])}' oldfile > newfile

Regards,
Alister

Yes, you are right. My conclusion was prematured (I judged before I even tried it).
Thanks