How do I scroll up and see previous displayed lines in the output?
I'm using QB64, and had to run a program 1000 times, but I cannot see the starting lines. Actually, I can't see the first 800 lines or so.
Is there a way to expand the window or scroll up to see everything? Because I do not have a scroll bar, and if I use any key to scroll up, it exits the console window.
Thanks in advance.
The new version of QB64 supports a console window, which should be able to do what you want. I'm not too used to console though, but if all else fails you could always save the text in a string array and examine that. There are some examples of creating lists in the community at qb64.net or you could make your own list with scrollbars, etc.
Input a line in the loop for data output:
if x > 24 then
if 24 MOD x then sleep
endif
MOD is the command for modulus where the modulus will return the remainder of 24 and x. in this case if it is zero then it will pause the console output until the user presses any key.
If you don't want to mess with custom buffers, just use the console:
$CONSOLE:ONLY
_DEST _CONSOLE
With that in the begining of your program, QB64 will create only a console window, which by default can be scrolled back so the past lines can be seen.
Related
For example, I am doing
console.log('Press A to Stop')
for(var i=0;i<10000;i++) console.log(i);
I want that the message Press a To Stop, will continue to appear all the time.
Do you have any idea how to do that?
The only solution I think about, is to calcuare number rows in the screen, and render frame after frame, (x-1 rows), and add the bottom row each time.
More Info
I want to show logs on the screen. (queries, requests, errors, and more), and I want the user to be able to change the log level, I want to show the instruction on the screen while he seeing the logs.
It's actually pretty easy, but you can't use console.log (which isn't a biggie in your case).
What you will need to do is the following:
instead of console.log use process.stdout.write(x) where x is the output you want (followed by a new line character \n)
use process.stdout.write("Press A to Stop"); (note there is no new line character at the end)
right before you need to write the next line of information use process.stdout.clearLine(); which clears what's currently on the last line of the output
repeat steps 1 to 3
I want to know if anyone does know a way to dump or copy the whole lot of viewable messages in a xterm window on linux. The very important thing is I don't want to know how to send a command out and kapture its output for stream 1 and 2 as well as the input, as this is well known to me.
I may explain for what this is needed. You do something and expect not any complications but than you got pages of msg's als err msg or normal output. To be able to see later after it you should be able to get them in a file and as long as you are able to scroll that all back and forther with your mouse it is sure the data is there some where. But the time may be not to scroll and screenshot and scroll ....
I would be glad to help me out in such cases and it would be fine to have the full view including all your own typing and all the msg's in same order as you watch it when you scroll it back.
I don't really know where this is stored and how you could get that saved. I know that I could dump the whole lot of Memory and search it for a part of the xterm window, but that is a bit over the top I think.
There is a control sequence, which I had forgotten. This question reminded me. In XTerm Control Sequences, it is noted "print all pages":
CSI ? Pm i
Media Copy (MC, DEC-specific).
Ps = 1 -> Print line containing cursor.
Ps = 4 -> Turn off autoprint mode.
Ps = 5 -> Turn on autoprint mode.
Ps = 1 0 -> Print composed display, ignores DECPEX.
Ps = 1 1 -> Print all pages.
That dates from 1999 (patch #119), so you likely have it in your xterm. You could do this in a shell command like this:
printf '\033[?11i'
A comment mentions the page Hidden gems of xterm, which uses the corresponding action print-everything (something that can be executed via the translations resource). It is in the manual page, of course. The same comment points to Extra characters in XTerm printerCommand output, which mentions the resource printAttributes. By default, the control sequences for the printer tell xterm to send extra control characters (to reconstruct video attributes). The resource can be modified (set to 0) to suppress that. That is even older (patch #74).
Without that — Conceivably one could construct an application which used the X SendEvent protocol to construct a series of events which would be interpreted as xterm actions to scroll back, select text and copy it chunk-by-chunk via the clipboard. You could even write it in Perl (there is a module for X protocol). But seriously, no.
If you want to capture text which was written to xterm, you can do this by preparing before the text is needed by different methods (see manual):
turn on the xterm logging feature (not that user-friendly because it generates the filename). This can be enabled using the "Log to File (logging)" menu entry.
use the printer control sequences to write lines as they are written (again, not that friendly, though there is a menu entry to turn it on and off, "Redirect to Printer (print-redir)")
use script to capture all output to the terminal. I use this, because it works with any terminal on any POSIX-like system (even Cygwin).
Each of these methods produces a file containing escape/control sequences, which requires filtering out. The hypothetical program using SendEvent could in principle eliminate that.
When installing things in Linux I often see stdout change after printing eg. there might be a counter showing installation progress that starts at 1% and goes up to 100%. How is this done? When I write C programs and I print something using printf, I can't change it afterwards - if I type 1%, it stays that way. How is it done? Is there a different function I have to use?
\r brings you back to the beginning of the line without issuing the \n to go to the next line. Use this to overwrite text on the screen to build progress bars, etc.
See:
How to add a progress bar to a shell script?
I used some sql command to join two tables and the result was two terminal line long for each row of resulted table.
I dont want so ... i mean is there any way to get scroll bar at the bottom so that a row can be fit into a terminal line. and it will be a well structured and readable output
I hope you get my question.
There is no way on a standard terminal. You could use e.g. less as your pager for you sql-client.
I propose to pipe the output into the command less -S:
$ mysql-command-doing-the-SELECT | less -S
(To achieve this in the interactive mysql console, you can type pager less -S.)
Then all lines are displayed without being wrapped, and you can scroll sideways using the arrow keys. You can also use the command less (without the option -S) and then interactively type - S to achieve the non-wrapping. (Type again to toggle.)
If you need a real scroll bar, I propose to pipe the output into a real file and then use a more sophisticated program like gedit (which can be switched to a non-wrapping display) to display it with a decent scroll bar.
Another solution: copy the data from the terminal and paste it into your favorite editor. The copied text will not have any line breaks "\n".
(Offtopic: on a linux system you can just select the text with a mouse and mouse-middle-click in your editor. This will copy the text without filling out the main copy-paste buffer.)
When you scroll up, say to see a log, the first portion of it will not be visible since the terminal only supports a limited no. of lines. So if you want to scroll up and be able to see everything, at least a few pages up, how do you do it?
Use Shift+Page Up and Shift+Page Down.
Piping the output to a pager like the following is a better choice:
command | less
command | more
You can enable unlimited scroll back (or a huge amount if you want).
To do this, go to
File → Profile preferences → Scrolling [tab]
Then, check Unlimited, or set the number of lines desired. And of course, it only applies to the next typed lines.
Some tricks I use-
some terminal applications (gnome-terminal) allow you to increase the scroll-back buffer size
pipe output to a file:
command > file.log
pipe your command to less:
command | less
tail log and pipe to grep to reduce output
tail -f example.log | grep 'search text'
An alternative to screen is using tee to copy all output to a file while still printing it on the terminal:
yourcommand | tee output.txt
Try using the screen command, and set its scrollback buffer to a larger size.
screen has many other benefits and wonderful features.
If all you're doing is looking at a log, you could alternately use a pager such as less
If you want to scroll line by line, you can use
Control+Shift+Up/Down Arrows.
If you are using gnome-term (the default), then you can change your settings. Either set the no. of lines to unlimited, or to a much larger buffer size than the default.
Essentially seconding to #zerick's solution but if you're on gnome-terminal you can modify its config. See this.
If you are in tmux (can create multiple terminal sessions in a single terminal session, highly recommended), you can easily use your normal navigation keys to scroll around after you do Ctrl-b then [, for more details let's take a look at: How do I scroll in tmux?
None of these answer the original question. All answers are how to make new terminal windows (or current one) start behaving a certain way. The question is about how to see whats already scrolled away.
To answer this, each terminal session should have it's own "history" file (not to be confused with what command history is) containing all the stuff that relates to stdin/stdout displayed. I could be wrong but this may be different depending on the terminal emulator you use. Some just trash it when you close the window/ end the session.
I am trying to get this figured out myself so here is the more direct answer in a different thread.
https://unix.stackexchange.com/questions/145050/what-exactly-is-scrollback-and-scrollback-buffer
From what this tells me, I suspect best advice you can get is, for whatever terminal emulator you use, look for where it stores the scrollback buffer and that might be your only hope. It's what I am going to try right now. (and that is IF the session is currently still open, not closed terminal windows)