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Can someone help me understand printf's alignment function. I have tried reading several examples on Stack and general Google results and I'm still having trouble understanding its syntax. Here is essentially what I'm trying to achieve:

HOLDING 1.1.1.1 Hostname Potential outage! SKIPPING 1:1:1:1:1:1:1:1 Hostname Existing outage!

I'm sorry, I know this is more of a handout than my usual questions. I really don't know how to start here. I have tried using echo -e "\t" in the past which works for horizontal placement, but not alignment. I have also incorporated a much more complex tcup solution using a for loop, but this will not work easily in this situation.

I just discovered printf's capability though and it seems like it will do what I need, but I dont understand the syntax. Maybe something like this?

A="HOLDING" B="1.1.1.1" C="Hostname" D="Potential outage" for (( j=1; j<=10; j++ )); do printf "%-10s" $A $B $C $D echo "\n" done

Those variables would be fed in from a db though. I still dont really understand the printf syntax though? Please help

* ALSO *

Off topic question, what is your incentive for responding? I'm fairly new to stack exchange. Do some of you get anything out of it other than reputation. Careers 2.0? or something else? Some people have ridiculous stats on this site. Just curious what the drive is.

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    Your question about reputation would be better asked on the Meta Stack Overflow site. The incentive for responding is reputation, and the satisfaction of helping other people. Some people may have gotten new jobs out of having a high reputation on SO, but it is not a reliable way of going after a new job. Commented Jan 19, 2014 at 2:19
  • There are other forums where people help each other. comp.lang.* usenet groups and websites like javaranch.com. The reputation is ingenious and invaluable in my opinion. Absent reputation you would have fewer people answering and patroling, and you also would get a different type of "answer" as seen in the other forums. It would often begin with "What are you trying to do". And before they would answer your question you would get a lecture from the standpoint of a language insider. And you might only get a lecture. The reputation turns it into a competition where the lecture part is minimized. Commented Jan 19, 2014 at 2:55

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The string %-10s can be broken up into multiple parts:

  • % introduces a conversion specifier, i.e. how to format an argument
  • - specifies that the field should be left aligned.
  • 10 specifies the field width
  • s specifies the data type, string.

Bash printf format strings mimic those of the C library function printf(3), and this part is described in man 3 printf.

Additionally, Bash printf, when given more arguments than conversion specifiers, will print the string multiple times for each argument, so that printf "%-10s" foo bar is equivalent to printf "%-10s" foo; printf "%-10s" bar. This is what lets you specify all the arguments on the same command, with the %-10s applying to each of them.

As for people's motivation, you could try the meta site, which is dedicated to questions about stackoverflow itself.

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This helps, but im still not having any luck. Can you give me an example please?

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