Unable to make Less to indicate location in percentage

Question

Thank you to Alex in showing me how to put a percentage sign in Less!

I now aim to show the percentage sign also when you run, for example, the command

man emacs

If you run it, you get 'byte 3300' for instance.

Alex's answer suggests me that we need to make a separate shell function by

man "$1"| col -b > /tmp/manual
less /tmp/manual

where $1 refers to the first parameter.

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The new problem is at the thread. Thanks to Yuliy for the crux move!

Answer 1

export LESS="-m"

More generally, the LESS environment variable may contain options equivalent to command line flags you could explicitly pass when running less -- here, the -m option that tells it to prompt more richly (including the percentage, as you asked). You could pass also more than one option within that single environment variable by ending each with a $. For much more info, see less's manpage.

Edit: it is of course possible (depending on how you're using less, e.g. if you're piping to it rather than calling it on a file) that less doesn't know the total size it will be displaying, in which case of course it can't show the % -- in that case it will prompt with what little info it does have, e.g., how much text has it shown so far. For example, man does use less that way, by piping.

So, if your specific need is to see the % in man (rather than when calling less directly on a file) you need to use an "alternate pager" (environment variable MANPAGER or switch -P on the man command line) which is a simple script that saves man's output to a temp file and then uses less on the latter. (That may lose man's own "colorization" unless you play yet further and deeper tricks, etc, etc -- similarly you might use the "preformat pages" option of man and uncompress such a preformatted page to a tempfile on which to run less, etc, but this is starting to become a somewhat complex "simple script";-).

Answer 2

I have this in my environment. It'll print <filename> - Lines X-Y of Z at the bottom, or at least as much of that information as it has.

export LESS='-P?f%f - .?ltLine?lbs. %lt?lb-%lb.?L of %L.:?pt%pt\%:?btByte %bt:-...'

Answer 3

To add to Alex Martelli' answer:

Note that you can also pass any command line parameter to less at runtime, by just typing it (including the -), followed by enter key. So you can just type

-m<Enter>

into a running less to toggle the long prompt.

This is especially useful for options that need to be changed at runtime, e.g. -S (line folding on/off).