History on Linux terminal

Sometimes, i typed a sensitive entry on Linux terminal and would like to clear history at once

player@srv:~$ sensitive enty
player@srv:~$ history -c
player@srv:~$ clear

An alternative way not to log the entry is to add a preceding space character

player@srv:~$ [space character]sensitive entry

For future reference.

My LPI Exam 101 Summary

Today i took the exam of LPI Level 1 Exam 101. My score is 570, which is a bit greater than the required score 500. Here are the details

Section Analysis	Percent Correct
Hardware & Architecture	66%
Linux Installation & Package Management	81%
GNU & Unix Commands	60%
Devices, Linux Filesystem, FHS	56%
The X Windows System	71%

Some notable points:

• This exam appointment was directly made from Prometric without further confirmation with the local test center. The test center staff recommended that i should inform them after online booking of next exam.
• The exam questions mainly focus on the application.
• The result proved the i havent well prepared.

Aside: When i began to touch Linux, i have ever posted a foolish question

hi,
i wanna buy a LCD monitor recently but don't know what brands are support by RH 8.0. could anyone give me some guides or tell me where can i find the solution.

Thanks

Screen shifted to the right on FC7

Description

For my Windows XP/Fedora Core 7 (GNOME Desktop) dual-boot machine (nVidia TNT2/Dell 1708FP LCD), 1024x768 resolution looks fine on WinXP but has a right shift on FC7. It seems due to the improper refresh rate setting. However, only refresh rate of 60Hz is selectable under 1024x768 in System>Preferences>Hardware>Screen Resolution. Changing horizontal screen position through LCD's OSD menu fixed the problem in FC7, and the display in WinXP would be affected at the same time.

Solution

First take a look on Xorg configuration file (/etc/X11/xorg.conf) in my machine.

Listing 1. Excerpt of /etc/X11/xorg.conf (original)

Section "Monitor"
        Identifier   "Monitor0"
        ModelName    "DELL 1708FP"
        HorizSync    31.0 - 48.5
        VertRefresh  50.0 - 76.0
        Option      "dpms"
EndSection

Section "Device"
        Identifier  "Videocard0"
        Driver      "nv"
EndSection

Section "Screen"
        Identifier "Screen0"
        Device     "Videocard0"
        Monitor    "Monitor0"
        DefaultDepth     24
        SubSection "Display"
        Viewport   0 0
        Depth     24
        EndSubSection
EndSection

It was generated by system-config-display. In this case, the attributes inside "Monitor" section is likely unsuitable for the Dell LCD. i have to manually edit the configuration file according to the useful information in Xorg log. Following the guide and example, it is not very hard to go through.

In my Xorg log, the optimized values for DELL1708FP can be found as follows.

Listing 2. Excerpt of /var/log/Xorg.0.log

(II) NV(0): Supported additional Video Mode:
(II) NV(0): clock: 108.0 MHz   Image Size:  338 x 270 mm
(II) NV(0): h_active: 1280  h_sync: 1328  h_sync_end 1440 h_blank_end 1688 h_border: 0
(II) NV(0): v_active: 1024  v_sync: 1025  v_sync_end 1028 v_blanking: 1066 v_border: 0
(II) NV(0): Serial No: PM06175RG051
(II) NV(0): Monitor name: DELL 1708FP
(II) NV(0): Ranges: V min: 56  V max: 76 Hz, H min: 30  H max: 81 kHz, PixClock max 140 MHz

The texts in bold are what i need for editing Xorg configuration file

• V min, V max: the range of VetRefresh in xorg.conf;
• H min, H max: the range of HorizSync in xorg.conf;
• PixClock max, h_active, h_sync, h_sync_end, h_black_end, v_active, v_sync, v_sync_end: for the added attribute ModeLine in xorg.conf.

Here is the modified "Monitor" section in xorg.conf.

Listing 3. Excerpt of /etc/X11/xorg.conf (modified)

Section "Monitor"
        Identifier   "Monitor0"
        ModelName    "DELL 1708FP"
        HorizSync    30.0 - 81.0
        VertRefresh  56.0 - 76.0
        ModeLine     "1280x1024" 140.0 1280 1328 1440 1688 1024 1025 1028 1066
        Option      "dpms"
EndSection

For the changes to take effect, need to log out and log in. Now i can select 3 refresh rates (60Hz, 70Hz, 75Hz) under 1024x768 in System>Preferences>Hardware>Screen Resolution. And the right shift disappeared at 70Hz.

Reference

http://xorg.freedesktop.org/wiki/FAQVideoModes