Bash printf prefix

Question

In Bash I can use printf to format a string output like this:- (Note how I've added a suffix of W to the string and that this is not included in the padding)

$ printf "Blah %11.1fW\n" 123 456 78965 5 56
Blah       123.0W
Blah       456.0W
Blah     78965.0W
Blah         5.0W
Blah        56.0W

If I want to prefix the string I could do this:-

$ printf "Blah £%11.1f\n" 123 456 78965 5 56
Blah £      123.0
Blah £      456.0
Blah £    78965.0
Blah £        5.0
Blah £       56.0

However note how this results in the padding being applied before the prefix.

How (if at all possible) would I use printf to prefix the value before padding so the output would be as follows:-

Blah      £ 123.0
Blah      £ 456.0
Blah    £ 78965.0
Blah        £ 5.0
Blah       £ 56.0

If not possible any Bash solution would be appropriate.

Are the accountants happy with this? In my experience `printf` style rounding cause accountants to faint. — cdarke, Jul 05 '12 at 10:47
@cdarke lol. This is an example only. No accountants are involved ! — general exception, Jul 05 '12 at 10:51

UltraInstinct · Accepted Answer · 2012-07-05T11:44:31.500

4

I came up with this:

$ printf "Rate: %11s\n" $(printf "$%.1f " 12345 123)
Rate:    $12345.0
Rate:      $123.0

Just be sure the choose the correct %11s for your case.

It seems that you addressed that space problem yourself. For the sake of completeness, I will put that in here.

$ printf "Rate: %11s\n" $(printf "$%.1f " 12345 123) | sed 's/\$/\$ /g'
Rate:    $ 12345.0
Rate:      $ 123.0

Here's the solution given by @FatalError:

printf "Rate: %11b\n" $(printf '$\\0040%.1f ' 12345 123)
Rate:   $ 12345.0
Rate:     $ 123.0

edited Jul 05 '12 at 11:44

answered Jul 05 '12 at 10:36

UltraInstinct

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Aha yes, the problem with this is when you introduce the space between the currency symbol and the data. – general exception Jul 05 '12 at 10:42
Piping output into `sed 's/\£/\£ /g'` may help me here. – general exception Jul 05 '12 at 10:45
1

Without `sed`, you could: `printf "Rate: %11b\n" $(printf '$\\0040%.1f ' 12345 123)` – FatalError Jul 05 '12 at 11:42
@FatalError Thats an awesome solution!! :) – UltraInstinct Jul 05 '12 at 11:43
Eh, I don't like to wordsplit `$()` output but works in a pinch especially with printf. If Bash had some sort of `zip` function I'd probably use it 10 times a day for this sort of thing. – ormaaj Jul 05 '12 at 11:49

ormaaj · Answer 2 · 2012-07-05T11:34:55.670

3

Not possible. You'd need something like strfmon. Workaround:

$ a=(123 456 78965 5 56)
$ printf 'blah %*s %.1f\n' {,,,,}{$((10 - ${#a[n]})),£,"${a[n++]}"}
blah      £ 123.0
blah      £ 456.0
blah    £ 78965.0
blah        £ 5.0
blah       £ 56.0

edited Jul 05 '12 at 11:34

answered Jul 05 '12 at 11:16

ormaaj

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score 2 · Answer 3 · answered Jul 06 '12 at 10:58

While I love ormaaj's solution for keeping things in the shell, I don't like using subshells unless I really need them. And a line with both a subshell AND a pipe just seems ... unnecessary.

$ printf "Rate: %11.1f\n" 123 | sed 's/  \([0-9]\)/$ \1/'
Rate:     $ 123.0

Bash printf prefix

3 Answers3

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