How to add 100 spaces at end of each line of a file in Unix

Question

I have a file which is supposed to contain 200 characters in each line. I received a source file with only 100 characters in each line. I need to add 100 extra white spaces

Answer 1

Updated after Glenn's suggestion

Somewhat how Glenn suggests in the comments, the substitution is unnecessary, you can just add the spaces - although, taking that logic further, you don't even need the addition, you can just say them after the original line.

perl -nlE 'say $_," "x100' file

Original Answer

With Perl:

perl -pe 's/$/" " x 100/e' file

That says... "Substitute (s) the end of each line ($) with the calculated expression (e) of 100 repetitions of a space".

If you wanted to pad all lines to, say, 200 characters even if the input file was ragged (all lines of differing length), you could use something like this:

perl -pe '$pad=200-length;s/$/" " x $pad/e'

which would make up lines of 83, 102 and 197 characters to 200 each.

Answer 2

Another way in GNU awk using string-manipulation function sprintf.

awk 'BEGIN{s=sprintf("%-100s", "");}{print $0 s}' input-file > file-with-spaces

A proof with an example:-

$ cat input-file
1234jjj hdhyvb 1234jjj
6789mmm mddyss skjhude
khora77 koemm  sado666
nn1004  nn1004 457fffy
$ wc -c input-file
      92 input-file
$ awk 'BEGIN{s=sprintf("%-100s", "");}{print $0 s}' input-file > file-with-spaces
$ wc -c file-with-spaces
      492 file-with-spaces

Answer 3

You can use printf in awk:

awk '{printf "%s%*.s\n", $0, 100, " "}' filename > newfile

This printf will append 100 spaces at the end of each newline.

Answer 4

With awk

awk '{printf "%s%100s\n", $0, ""}' file.dat

$0 refers to the entire line.

Answer 5

If you want to have fixed n chars per line (don't trust the input file has exact m chars per line) follow this. For the input file with varying number of chars per line:

$ cat file
1
12
123
1234
12345

extend to 10 chars per line.

$ awk '{printf "%-10s\n", $0}' file | cat -e

1         $
12        $
123       $
1234      $
12345     $

Obviously change 10 to 200 in your script. Here $ shows end of line, it's not there as a character. You don't need cat -e, here just to show the line is extended.

Answer 6

Just in case you are looking for a bash solution,

while IFS=  read -r line
    do
    printf "%s%100s\n" "$line" 
done < file > newfile

---

Test

Say I have a file with 3 lines it it as

$ wc -c file
      16 file
$ wc -c newfile
     316 newfile

---

Original Answer

spaces=$(echo {1..101} | tr -d 0-9)
while read line
    do
    echo -e "${line}${spaces}\n" >> newfile
done < file