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Do less textfile | col and cat textfile accomplish the same thing?

I wonder if man mysql | col -b > textfile and man mysql > textfile do the same?

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  • Do you have an example in mind that you're asking these about? Commented Sep 14, 2014 at 18:10
  • Yes, see my edit. Commented Sep 14, 2014 at 18:17
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    I would say that given you're piping the output to col -b that they're different, in the sense, that if there are any backspaces within the output, the col -b will strip them away. Commented Sep 14, 2014 at 18:20

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That's completely different, since less may do various kinds of transformation, e.g. via $LESSOPEN.

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It's not quite the same, since when col can do something with output from less.

The important point here, less will copy input file to output if its output is not a tty. You can see in less-451 - main.c - line 222:

 /* * Set up terminal, etc. */ if (!is_tty) { /* * Output is not a tty. * Just copy the input file(s) to output. */ SET_BINARY(1); if (nifile() == 0) { if (edit_stdin() == 0) cat_file(); } else if (edit_first() == 0) { do { cat_file(); } while (edit_next(1) == 0); } quit(QUIT_OK); }

So, to do the same as cat file, you can:

less file | grep ^
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  • Even if less doesn't do anything special, your less file | grep . example is wrong, as grep . will/may filter out lines that do not contain valid characters. Commented Sep 14, 2014 at 18:40
  • @vinc17: Oh, my mistake, fixed it. Commented Sep 14, 2014 at 18:41

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