Retaining full manual for scrolling in SSH (Putty) terminal

Question

Beginners question:

I am reading a man page called in a ssh (putty) session, i.e:

man usermod

Now this man page has about 252 line, when reaching the end, I press q for quit. It would be very helpful if all the lines from man page would remain in the terminal window for scrolling, but it will be cropped, only last 50 lines stays in terminal window.

Probably very simple, but did not find a similar question.

Answer 1

From man man:

     MANPAGER  Any non-empty value of the environment variable MANPAGER is
               used instead of the standard pagination program, less(1). 

So, you would invoke man as such:

MANPAGER=cat man usermod

Alternatively, you can pipe through cat to disable paging:

man usermod | cat

Note: Some versions of man support the use of -c parameter, which does the same:

man -c usermod

Consult man(1) to confirm if your system supports it.

Answer 2

Don't quit the pager (q) until you have finished reading the documentation.

While you're still in the pager you can scroll up and down. For example, using less as the pager the corresponding keys are b, ↑, Page Up to scroll up/backwards, and Space, ↓, Page Down to scroll down/forwards.

Answer 3

Add export MANPAGER="less -X" to your ~/.bashrc and use only man usermod in your next bash session to keep less' output.

Answer 4

In other answers, advice is given for

• substituting cat for less to avoid whatever unspecified limitations the latter may have,
• staying in less to keep access to the content which works around the problem,
• using the -X option of less without mentioning why this addresses the issue, and
• using putty's option (in the Window dialog) to change the length of the scrollback.

However, on a different dialog (Terminal / Feature), putty allows one to suppress switching to the alternate screen. If those two features are combined, then putty will not switch to to the alternate screen when displaying the file (and on completion and quitting the pager as specified by OP) will not clear the screen, leaving the whole content available for scrolling using putty's built-in handling up page-up/page-down.

The -X option of less does something like that Terminal / Feature option:

       -X or --no-init
              Disables sending the termcap initialization and
              deinitialization strings to the terminal.  This is
              sometimes desirable if the deinitialization string does
              something unnecessary, like clearing the screen.

but does not address putty's limit on the number of lines retained on the window. OP may have chosen (or relied upon) a modified terminal description which omits smcup / rmcup (the terminfo capabilities that less ends up using), but did not mention this. Telling putty to do this resolves the ambiguity.

putty (like most of the terminal programs you would use) implements xterm's alternate screen feature. It is one of the (relatively few) to provide a way to suppress it at runtime: most simply hardcode the behavior as the original xterm did. Because of this prevalence of hardcoding, in a few cases, packagers have modified the terminal description to omit the feature, though preference for the feature appears to be equally split.

Answer 5

Using the pager mentioned in the other answers is what you can and should do.

However, to answer the question as asked: you can set up scrollback buffer size in PuTTY under Settings / Window / Lines of scrollback:

Note that it will help you only if you are not using less as a pager (the default on most systems these days): it will redraw the screen instead of scrolling.