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Re: what is the use of -c parameter of column(1), can you demonstrate with an example?



On 2010-11-17 13:12:38 +0800, Zhang Weiwu, Beijing wrote:
> While I see it this way:
> 
> expand    --> Format tab-indented text and tab-separated tables using spaces.
> column -t --> Format tab-separated tables using spaces.
> column    --> Format lists into columns.

"column -t" does much more than format tabs into spaces.

It can use a comma as a separator, for processing CSV data.

    column -t -s ',' myfile.csv

It can use a space as a separator, for processing "aptitude update".

    sudo aptitude update | column -t

It can use a colon as a separator, for processing "/etc/group".

    column -t -s ':' /etc/group

> Pick this scenario:
> 
> A user have tab-separated tabular data.
> 
> 1. He try to format it, using expand -t 8
> 2. He see it's not good enough, he does it again with expand -t 10
> 3. He see it's okay for some columns, but is too wide for others. Then he uses column -t

It seems to me that the only thing this scenario proves is that
sometimes you need to use "expand", and sometimes you need to
use "column -t". They are different tools, with different purposes.

> I follow the idea that usage leads to tools, that "you have tools for a
> usage", while traditional column tool seems to design from tools to
> usage, that "you have tools which can used for usages". I guess this is
> more rational from learning prospective.

The column utility was written to satsify a need! For any long skinny
list of text, it will put that list into *columns* that fit on the
screen better, so you don't have to do as much scrolling.

"column -t" also satisfies a need! It takes ragged columns of output
and spreads them out so they are nicely aligned... and therefore
readable.

I hope I have understood your argument correctly,

Phil


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