Using awk to align columns in text file?

Question

Would awk be useful to convert "Input" to "Desired output"?

Input

testing speed of encryption
test 0 (64 bit key, 16 byte blocks): 2250265 operations in 1 seconds (36004240 bytes)
test 1 (128 bit key, 64 byte blocks): 879149 operations in 1 seconds (56265536 bytes)
test 2 (128 bit key, 256 byte blocks): 258978 operations in 1 seconds (66298368 bytes)
test 3 (128 bit key, 1024 byte blocks): 68218 operations in 1 seconds (69855232 bytes)
test 4 (128 bit key, 8192 byte blocks): 8614 operations in 1 seconds (70565888 bytes)
test 10 (256 bit key, 16 byte blocks): 1790881 operations in 1 seconds (3654096 bytes)

Desired output

testing speed of encryption
test  0  (64 bit key,   16 byte blocks): 2250265 operations in 1 seconds (36004240 bytes)
test  1 (128 bit key,   64 byte blocks):  879149 operations in 1 seconds (56265536 bytes)
test  2 (128 bit key,  256 byte blocks):  258978 operations in 1 seconds (66298368 bytes)
test  3 (128 bit key, 1024 byte blocks):   68218 operations in 1 seconds (69855232 bytes)
test  4 (128 bit key, 8192 byte blocks):    8614 operations in 1 seconds (70565888 bytes)
test 10 (256 bit key,   16 byte blocks): 1790881 operations in 1 seconds  (3654096 bytes)

Chris Seymour · Accepted Answer · 2012-12-30 22:01:28Z

47

A trick to align right using column is to use rev:

$ head -1 file; tail -n+2 file | rev | column -t | rev
testing speed of encryption
test   0   (64  bit  key,    16  byte  blocks):  2250265  operations  in  1  seconds  (36004240  bytes)
test   1  (128  bit  key,    64  byte  blocks):   879149  operations  in  1  seconds  (56265536  bytes)
test   2  (128  bit  key,   256  byte  blocks):   258978  operations  in  1  seconds  (66298368  bytes)
test   3  (128  bit  key,  1024  byte  blocks):    68218  operations  in  1  seconds  (69855232  bytes)
test   4  (128  bit  key,  8192  byte  blocks):     8614  operations  in  1  seconds  (70565888  bytes)
test  10  (256  bit  key,    16  byte  blocks):  1790881  operations  in  1  seconds   (3654096  bytes)

answered Dec 30, 2012 at 22:01

Chris Seymour

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1 Comment

hardmooth Over a year ago

nice. However, this doesn't work if the last column has non-constant width.

Mike Sherrill 'Cat Recall' · Accepted Answer · 2012-12-30 23:51:44Z

24

Yes. Look at the syntax for awk's printf() function. Abbreviated sample code . . .

{
  printf("%s %2s ", $1, $2);
  printf("%4s %s %s ", $3, $4, $5);
  printf("%4s %s %s ", $6, $7, $8);
  printf("%7s\n", $9);
}

Output.

test  0  (64 bit key,   16 byte blocks): 2250265
test  1 (128 bit key,   64 byte blocks):  879149
test  2 (128 bit key,  256 byte blocks):  258978
test  3 (128 bit key, 1024 byte blocks):   68218
test  4 (128 bit key, 8192 byte blocks):    8614
test 10 (256 bit key,   16 byte blocks): 1790881

Docs for GNU awk's printf().

There are several ways to pass the "heading" through unmodified. This way assumes it's always on the first line of the file.

NR==1 { print $0}
NR>1 {
  printf("%s %2s ", $1, $2);
  printf("%4s %s %s ", $3, $4, $5);
  printf("%4s %s %s ", $6, $7, $8);
  printf("%7s\n", $9);
}

edited Dec 30, 2012 at 23:51

answered Dec 30, 2012 at 22:01

Mike Sherrill 'Cat Recall'

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4 Comments

Sandra Schlichting Over a year ago

Very interesting! Is it possible to have the header pass through without being aligned?

Eric Freese Over a year ago

As far as I can tell, this doesn't work reliably with strings with multibyte characters as the width modifier (4 in %4s) is counting bytes instead of what most people would consider "characters"

Mike Sherrill 'Cat Recall' Over a year ago

It counts characters on my box. Is your terminal Unicode-aware?

Paulo Carvalho Over a year ago

Good, because the column command can't handle large files (like 6GB or more).

Ed Morton · Accepted Answer · 2012-12-31 07:37:25Z

8

awk '
FNR==1 { if (NR==FNR) print; next }
NR==FNR {
   for(i=1;i<=NF;i++)
      w[i] = (w[i] <= length($i) ? length($i) : w[i])
   next
}
{
   for(i=1;i<=NF;i++)
      printf "%*s",w[i]+(i>1?1:0),$i
   print ""
}
' file file

answered Dec 31, 2012 at 7:37

Ed Morton

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1 Comment

Ciro Santilli OurBigBook.com Over a year ago

I think it should be if (NR==FNR) next? Here is a version that deals with stdin: stackoverflow.com/questions/12768907/…

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