Re: Command line: How do you keep the output from scrolling out of sight?
on 10:59 Tue 01 Mar, Jason Hsu (firstname.lastname@example.org) wrote:
> I'm using Debian in a command-line-only installation for running a
> I know that I'm supposed to use the messages I see every time I enter
> a command for troubleshooting purposes. But if the output is too
> long, then the first messages scroll out of sight, and that makes it
> impossible to properly troubleshoot when I don't know what I'm doing.
> Is there a way to get the output to temporarily stop so I can read it
> all if I wish?
As others have noted:
command | less
Or an alternate pager, from least to most featured: pg, more, most, dog.
You can specify this with the PAGER environment variable or under
/etc/alternatives/pager (see update-alternatives).
You can dump output to a file. Several varaints:
command >myfile # save standard output
command >myfile 2>&1 # save standard output & standard error
command >myfile 2>myfile.err # separate stdout/stderr
command >/dev/null # discard stdout (stderr displayed to terminal)
command | tee myfile # view output, save stdout to 'myfile'
command 2>&1 | tee myfile # view output, both stdout & stderr to 'myfile'
Your terminal's scrollbar should be generally useful. Set a
sufficiently large scrollback buffer.
Page-up / page-down, may work in some terminals and/or console.
The 'script' command can be used to record interactive sessions.
Depending on the amount of screen-painting going on (ncurses /
full-screen terminal programs such as top, etc.), this may not be too
readable. 'scriptreplay' may make for a saner output.
Using 'screen' one of the benefits is a scrollback buffer. Very handy.
For noninteractive comamnds, where I want to massage the output but
don't know what filters I need to use immediately (or want to see
command | vim - # read stdout into vim for interactive editing.
I can then annotate or use futher regex substitutions or commands to
clean up / modify data.
Mostly I just pipe output to less or redirect to a file as needed.
Dr. Ed Morbius, Chief Scientist / |
Robot Wrangler / Staff Psychologist | When you seek unlimited power
Krell Power Systems Unlimited | Go to Krell!