via a script - change Scrollback

[joseph22]

1000 Lines = current Adjust Scrollback - Konsole

Question:
Inside a Bash script, how to change Scrollback from
1000 Lines to
9999 Lines? via a script, not manually.

What is the script command?



using
Kubuntu 22.04 (Jammy Jellyfish)


konsole 21.12.3

Qt: 5.15.3
KDE Frameworks: 5.92.0
kf5-config: 1.0

--

[oshunluvr]

I don't think you can change it on-the-fly. IME, a change to the console requires a reloading of the console - basically logging out of it and re-opening it. Which seems unlikely that would do want you want.

I haven't tried this, but it seems you can reload your profile without logging out with this command:

. ~/.profile

IDK if you could set HISTFILESIZE there and reload it it might work. From the man page:

HISTFILESIZE
The maximum number of lines contained in the history file. When this variable is assigned a value, the history file is truncated, if necessary, to
contain no more than that number of lines by removing the oldest entries. The history file is also truncated to this size after writing it when a
shell exits. If the value is 0, the history file is truncated to zero size. Non-numeric values and numeric values less than zero inhibit truncation.
The shell sets the default value to the value of HISTSIZE after reading any startup files.

If you better explained what exactly you're trying to accomplish, someone might have a suggestion.

Points to ponder:
My HISTFILESIZE is set in ~/.bashrc at 20000. ~/.bash_history currently occupies less than a half-meg (before compression). Assuming you wanted 9999 and the storage was roughly equal - 250k. Not really that big of a file in the scheme of things.

If you want to expand, then trim the history file for some reason, you could set it at 9999, then truncate it when exiting the terminal via a command in ~/.bash_logout.

It's hard to guess what you want without explanation as to why or actual details.

[jlittle]

oshunluvr has advised about the bash history, but I think the OP has asked about the konsole "scrollback", in konsole Settings->Edit Current Profile...->Scrolling->Scrollback.

The settings for each profile stored are in ~/.local/share/konsole, and you can change the scrollback size there. For example, for a profile named "white",

 sed -i 's/HistorySize=[0-9]*/HistorySize=2200/' ~/.local/share/konsole/white.profile

(If the konsole has no or unlimited scrollback, that won't work, without any indication. "HistoryMode" has to be set to 1, then the HistorySize line added to the [Scrolling] section.)

This won't affect a running konsole using that profile. But that can be done with qdbus!

qdbus $KONSOLE_DBUS_SERVICE $KONSOLE_DBUS_SESSION org.kde.konsole.Session.setHistorySize 9999

(It's a long time since I've gone down the qdbus rabbit-hole and found something that works.)

[oshunluvr]

Silly me. I thought they were the same thing...

[joseph22]

qdbus $KONSOLE_DBUS_SERVICE $KONSOLE_DBUS_SESSION org.kde.konsole.Session.setHistorySize 9999

If Terminal scrollback is set to Unlimited,
then above code works as a Terminal command.

If Terminal scrollback is set to Fixed, then above code does not work.
scrollback remains at 1000 Lines not 9999 Lines.

background:
Ctrl-Alt-T = Terminal / right click / adjust scrollback / Fixed size 1000 Lines

or

If task is too difficult to do in a script
then how to manually and permanently change scrollback to
99123 Lines?


because the scrollback windows says:
Any adjustments are only temporary to this session.

--

[jlittle]

qdbus $KONSOLE_DBUS_SERVICE $KONSOLE_DBUS_SESSION org.kde.konsole.Session.setHistorySize 9999

If Terminal scrollback is set to Fixed, then above code does not work.
scrollback remains at 1000 Lines not 9999 Lines.

The setting as seen in edit profile screen does not change, but the actual amount of scrollback changes for me. If I fix the scrollback to 1000 in the settings, restart the console, then run seq 2000, then scroll all the way back using the scrollbar thumb, the bottom line is 1001. If I then run the qdbus command to set the size to 100, the thumb increases in size greatly and if I use it to scroll all the way back the bottom line is 1903. If I use the qdbus command to set it to 0, the konsole doesn't scroll at all. The profile setting is unchanged, and will be used for new windows with that profile; to change that edit the .profile file.

how to manually and permanently change scrollback...

Well, edit the .profile file. I copy those between systems, and back them up with (lots of) other "dotfiles".

[joseph22]

Well, edit the .profile file. I copy those between systems, and back them up with (lots of) other "dotfiles".

Hello jlittle
What is the command inside .profile?

How to change Scrollback from
1000 Lines to
9999 Lines?



Found file at

/home/X/.profile

above file says :



# ~/.profile: executed by the command interpreter for login shells.
# This file is not read by bash(1), if ~/.bash_profile or ~/.bash_login
# exists.
# see /usr/share/doc/bash/examples/startup-files for examples.
# the files are located in the bash-doc package.

# the default umask is set in /etc/profile; for setting the umask
# for ssh logins, install and configure the libpam-umask package.
#umask 022

# if running bash
if [ -n "$BASH_VERSION" ]; then
# include .bashrc if it exists
if [ -f "$HOME/.bashrc" ]; then
. "$HOME/.bashrc"
fi
fi

# set PATH so it includes user's private bin if it exists
if [ -d "$HOME/bin" ] ; then
PATH="$HOME/bin:$PATH"
fi

# set PATH so it includes user's private bin if it exists
if [ -d "$HOME/.local/bin" ] ; then
PATH="$HOME/.local/bin:$PATH"
fi

[jlittle]

What is the command inside .profile?

The konsole settings have nothing to do with the ".profile" in your home directory.

I'm sorry, because you asked for "bash script" I assumed you'd understand "The settings for each profile stored are in [console]~/.local/share/konsole[/console], and using an example for a konsole profile file called "white" with a command that referred to [console]~/.local/share/konsole/white.profile[/console] would be enough.

The sed command I gave would fit naturally in a bash script, though it is for a particular profile name. One could remove that with

konsole_profile=$(qdbus $KONSOLE_DBUS_SERVICE $KONSOLE_DBUS_SESSION org.kde.konsole.Session.profile)
sed -i 's/HistorySize=[0-9]*/HistorySize=2200/' ~/.local/share/konsole/$konsole_profile.profile

but I suspect I'm going too far.

[joseph22]

I assumed you'd understand

i do not understand.


If you have time then clarify.

Is code for a bash script?
an on the fly code that can change total Lines with each script
or
Is code for a permanent setting?

What code goes to which file?
using Kubuntu 22.04

etc.


The problem:
1000 Lines fixed is system default and is too small

changing 1000 Lines to 9999 Lines manually, is only temporary per session
changing 1000 Lines to unlimited Lines manually, is only temporary per session
changing 1000 Lines to unlimited is not desired
changing 1000 Lines to 100 million Lines or 99,999,999 is desired versus unlimited



Question is:
How to change Scrollback from
1000 Lines to
9999 Lines?

How to change Scrollback via a script? was the first question.
How to change Scrollback via a permanent setting is Ok too.

--

[Snowhog]

How to change Scrollback via a permanent setting is Ok too.

That's easy enough. Launch Kate and open the file .bashrc (the period is part of the file name). Change the value for HISTSIZE and HISTFILESIZE as desired. HISTFILESIZE is the maximum number of lines contained in the history file. HISTSIZE is the number of commands to remember in the command history.

You can read about this by searching for man bash in your browser.

[joseph22]

That's easy enough.
Launch Kate and open the file
.bashrc
(the period is part of the file name).
Change the value for HISTSIZE and HISTFILESIZE as desired.
HISTFILESIZE is the maximum number of lines contained in the history file.
HISTSIZE is the number of commands to remember in the command history.
You can read about this by searching for man bash in your browser.

kate ~/.bashrc

or said differently

kate /home/X/.bashrc

changed to
HISTSIZE=9999
HISTFILESIZE=9999999


Closed all windows
Restart computer
Opened Terminal

seq 11041

result:
11041 bottom Line
10001 top Line, Ctrl-Shift-Home
------------------------------------------
_1040 total displayed Lines


but total displayed Lines is too small.
How come?

[Snowhog]

but total displayed Lines is too small.
How come?

Read up about this by searching for man bash in your browser.

[joseph22]

Read up about this by searching for man bash in your browser.

man bash excerpt:


HISTFILE
The name of the file in which command history is saved (see HISTORY below). The default value is ~/.bash_history.
If unset, the command history is not saved when a shell exits.

HISTFILESIZE
The maximum number of lines contained in the history file. When this variable is assigned a value, the history file
is truncated, if necessary, to contain no more than that number of lines by removing the oldest entries. The history
file is also truncated to this size after writing it when a shell exits. If the value is 0, the history file is truncated to zero size. Non-numeric values and numeric values less than zero inhibit truncation. The shell sets the default value to the value of HISTSIZE after reading any startup files.

HISTIGNORE
A colon-separated list of patterns used to decide which command lines should be saved on the history list. Each pat‐
tern is anchored at the beginning of the line and must match the complete line (no implicit `*' is appended). Each
pattern is tested against the line after the checks specified by HISTCONTROL are applied. In addition to the normal
shell pattern matching characters, `&' matches the previous history line. `&' may be escaped using a backslash; the
backslash is removed before attempting a match. The second and subsequent lines of a multi-line compound command are not tested, and are added to the history regardless of the value of HISTIGNORE. The pattern matching honors the setting of the extglob shell option.

HISTSIZE
The number of commands to remember in the command history (see HISTORY below). If the value is 0, commands are not saved in the history list. Numeric values less than zero result in every command being saved on the history list
(there is no limit). The shell sets the default value to 500 after reading any startup files.

HISTTIMEFORMAT
If this variable is set and not null, its value is used as a format string for strftime(3) to print the time stamp
associated with each history entry displayed by the history builtin. If this variable is set, time stamps are writ‐
ten to the history file so they may be preserved across shell sessions. This uses the history comment character to
distinguish timestamps from other history lines.

man bash has 4419 lines


Question:
How to permanently change Scrollback from
1000 Lines to
9999 Lines? or more