Find Longest Line in a .txt File and fill all Lines to that Length with 'blank Spaces'?

Usually I find that this type of question is a result of this thought process:

1. I am trying to solve problem A
2. I think doing process B will solve A
3. I will ask how to achieve process B

You will get literal answers on how to achieve process B - but if you include thecontext of problem A, you will get better answers and probably one that solvesproblem A in a simpler manner than process B.

So, what problem are you trying to solve by making all the lines in a file the same length?

This is all you need:

pr  -W 80 -mtT file1 file2

Or, more verbosely:

pr --page-width=80 --merge --omit-header --omit-pagination file1 file2

Vary the number to change the layout of the result.

You can use wc to count the number of characters in a line. Measure all lines in the file to find the longest length. For all other files, (max length - line length) gives you the number of space characters to print at the end of the line (which you can do with printf).

Update:Is using awk a requirement? If not, try this:

# Measure the longest line in the filemaxlen=`wc -L filename.txt | cut -d ' ' -f 1`# Pad each line to $maxlen characterswhile read linedo    printf "%-${maxlen}s\n" "$line" >> outfile.txtdone < filename.txt

Edit #2:If you don't have the -L option to wc, you can calculate the length of the longest line using the following loop:

maxlen=0while read linedo    thislen=`echo $line | wc -c`    [ $[$thislen>$maxlen] ] && maxlen=$thislendone < filename.txt

The ending value of $maxlen will be the length of the longest line.