리눅스 매직 키

Using the Magic SysRq Key

The SysRq key is located near the Scroll Lock key on your keyboard – the Sys Rq key is generally the same as your Print Screen key. The “magic” SysRq combination is Alt+SysRq.

To use this key combination, your Linux kernel must have been compiled with the CONFIG_MAGIC_SYSRQ compile option – most Linux distributions will have this enabled by default. Assuming it’s compiled into your kernel, it can be enabled or disabled on a running system by changing the value of /proc/sys/kernel/sysrq. To check if it’s enabled, run the following command:

    cat /proc/sys/kernel/sysrq

If you see a “1”, the magic SysRq key is enabled.

image

If you see a “0”, you’ll have to enable it yourself by running the following command as root:

    echo “1” > /proc/sys/kernel/sysrq

Dealing With a Frozen X Server

If your X server (the program that runs your graphical desktop) freezes, you may find yourself unable to use your system. There are a few magic SysRq commands that can help:

    Alt + SysRq + r – Takes the keyboard out of raw mode, taking control away from the X server. After running this combination, you should be able to use the Ctrl + Alt + F1 (and other F-key) keyboard shortcuts to switch to another console and restart X.
    Alt + SysRq + k – Kills all programs on the current virtual console, including X. You can also enable the Ctrl+Alt+Backspace keyboard shortcut in Ubuntu’s keyboard preferences to restart your X server – however, this shortcut is implemented by the X server and may not always work.

Cleanly Restarting Your System

Used in sequence, some of these actions can be used to cleanly end processes, flush data to disk, unmount all file systems, and restart your computer. To perform this process, press and hold the Alt + SysRq key combination and – while holding the Alt and SysRq keys down — type the following keys in order, pausing for several seconds in between each key:

    reisub

The mnemonic “Raising Elephants Is So Utterly Boring” is often used to remember this sequence. Here’s what each key does:

    r – Puts the keyboard into raw mode, taking control of it away from the X server.
    e – Sends the terminate signal to all processes, asking them to end gracefully.
    i – Sends the kill signal to all processes, forcing them to end immediately.
    s – Flushes data from your cache to disk.
    u – Remounts all file systems read-only.
    b – Reboots your computer.

More Commands

Here are some other actions you can perform with the magic SysRq key. To perform an action, press and hold the Alt + SysRq keys while typing the letter:

    n – Resets the nice level (priority) of all high and realtime priority processes.
    f – Calls oom_kill, which will kill a memory-hogging process.
    o – Shuts off the computer.

There are other actions, but they may be more useful to developers than the average Linux geek. For more information on the magic SysRq key – and a full list of actions you can perform – consult the sysrq.txt file included with the Linux kernel.

freebsd magic key

* How do I use the magic SysRQ key? ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ On x86 - You press the key combo 'ALT-SysRQ-<command key>'. Note - Some (older?) may not have a key labeled 'SysRQ'. The 'SysRQ' key is also known as the 'Print Screen' key.

On SPARC - You press 'ALT-STOP-<command key>', I believe.

On PowerPC - You press 'ALT-Print Screen-<command key>'.

On other - If you know of the key combos for other architectures, please let me know so I can add them to this section.

* What are the 'command' keys? ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 'r' - Turns off keyboard raw mode and sets it to XLATE.

'k' - Kills all programs on the current virtual console.

'b' - Will immediately reboot the system without syncing or unmounting your disks.

'o' - Will shut your system off (if configured and supported).

's' - Will attempt to sync all mounted filesystems.

'u' - Will attempt to remount all mounted filesystems read-only.

'p' - Will dump the current registers and flags to your console.

't' - Will dump a list of current tasks and their information to your console.

'm' - Will dump current memory info to your console.

'0'-'9' - Sets the console log level, controlling which kernel messages will be printed to your console. ('0', for example would make it so that only emergency messages like PANICs or OOPSes would make it to your console.)

'e' - Send a SIGTERM to all processes, except for init.

'i' - Send a SIGKILL to all processes, except for init.

'l' - Send a SIGKILL to all processes, INCLUDING init. (Your system will be non-functional after this.)

* Okay, so what can I use them for?

freebsd consol screen size change

    280 (0×118) 0x0000001f G 1024x768x32 D   8×16  0xa0000 64k 64k 0xf3000000 3072k

(mode 280 is 1024 x 768 in 32-bit colour and uses a 8×16 font)

This is the mode I want to use, and I want to increase my geometry from 80×25 to 132×60, so I can type the following command to one-time set it:

    vidcontrol -g 132×60 MODE_280 < /dev/console

 /etc/rc.conf file:

    allscreens_flags="-g 132×60 MODE_280"

 /boot/loader.conf file:

    vesa_load="YES"

FreeBSD 10 color csh shell [컬러쉘사용 위한 설정]

 /etc$ cat profile

#csh
setenv LANG ko_KR.UTF-8
setenv LC_ALL ko_KR.UTF-8

#bash
#export LANG=ko_KR.UTF-8
#export LC_ALL=ko_KR.UTF-8

export LSCOLORS=hxgxbxBxHxfxDxHxHxhxhx

root@hostname :/etc # cat csh.cshrc

# $FreeBSD: release/10.0.0/etc/csh.cshrc 50472 1999-08-27 23:37:10Z peter $
#
# System-wide .cshrc file for csh(1).
setenv LANG ko_KR.UTF-8
setenv LC_ALL ko_KR.UTF-8

set prompt="%{\e[32;1m%}%n%{\e[37m%}@%{\e[33m%}%m%{\e[37m%}:%{\e[36m%}%~%{\e[37m%}"\$"%{\e[0m%} "

alias ls        ls -FG

/usr/ports 의 make clean 진행

/usr/ports 의 make clean 진행

#!/bin/sh
#
# Search for ports that contain a "work" subdirectory,
# then go into that port directory and perform a
# make clean

for i in `find /usr/ports -name work -type d`
 do
  cd `echo "$i" | sed 's/\/[^\/]*$/\//'`
  make clean
 done

아래는 모두클린

cd /usr/ports && make clean

freebsd 시스템 튠닝 관련 명령

freebsd 시스템 튠닝 관련 명령

프비 비프음 끄기

# sysctl hw.syscons.bell=0

Make sure settings remains same after you reboot the laptop, enter:
 
# echo "hw.syscons.bell=0" >> /etc/sysctl.conf

Test it:
 
# reboot