linux_faq.lyx

CNC 的开放码,EMC2 V2.2.8版

#LyX 1.3 created this file. For more info see http://www.lyx.org/
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\layout Chapter

Linux FAQ
\begin_inset LatexCommand \index{Linux FAQ}

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These are some basic Linux commands and techniques for new to Linux users.
 More complete information can be found on the web or by using the man pages.
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Automatic Login
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When you install EMC2 with the Ubuntu LiveCD the default is to have to log
 in each time you turn the computer on.
 To enable automatic login go to System/Administration/Login Window.
 If it is a fresh install the Login Window might take a second or three
 to pop up.
 You will have to have your password that you used for the install to gain
 acess to the Login Window Preferences window.
 In the Security tab check off Enable Automatic Login and pick a user name
 from the list (that would be you).
 
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Man Pages
\begin_inset LatexCommand \index{Man Pages}

\end_inset 


\begin_inset LatexCommand \label{sec:Man-Pages}

\end_inset 


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Man pages are automatically generated manual pages in most cases.
 Man pages are usually available for most programs and commands in Linux.
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To view a man page open up a terminal window by going to Applications, Accessori
es, Terminal.
 For example if you wanted to find out something about the find command
 in the terminal window type:
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man find
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Use the Page Up and Page Down keys to view the man page and the Q key to
 quit viewing.
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List Modules
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Sometimes when troubleshooting you need to get a list of modules that are
 loaded.
 In a terminal window type:
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lsmod
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If you want to send the output from lsmod to a text file in a terminal window
 type:
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lsmod > mymod.txt
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The resulting text file will be located in the home directory if you did
 not change directories when you opened up the terminal window and it will
 be named mymod.txt or what ever you named it.
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Editing a Root File
\begin_inset LatexCommand \index{Editing a Root File}

\end_inset 


\begin_inset LatexCommand \label{sec:Editing-a-Root}

\end_inset 


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When you open the file browser and you see the Owner of the file is root
 you must do extra steps to edit that file.
 Editing some root files can have bad results.
 Be careful when editing root files.
 You can open and view most root files normally but they will open in 
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read only
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 mode.
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The Command Line Way
\begin_inset LatexCommand \index{sudo gedit}

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Open up Applications, Accessories, Terminal.
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In the terminal window type:
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sudo gedit
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Open the file with File, Open then edit
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The GUI Way
\begin_inset LatexCommand \index{gksudo}

\end_inset 


\layout Enumerate

Right click on the desktop and select Create Launcher
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Type a name in like sudo edit
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Type 
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\series bold 
gksudo 
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gnome-open %u
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\end_inset 


\family default 
\series default 
 as the command and save the launcher to your desktop
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Drag a file onto your launcher to open and edit
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Terminal Commands
\begin_inset LatexCommand \index{Terminal Commands}

\end_inset 


\begin_inset LatexCommand \label{sec:Terminal-Commands}

\end_inset 


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Working Directory
\begin_inset LatexCommand \index{Working Directory}

\end_inset 


\begin_inset LatexCommand \index{pwd}

\end_inset 


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To find out the path to the present working directory in the terminal window
 type:
\layout LyX-Code

pwd
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Changing Directories
\begin_inset LatexCommand \index{Changing Directories}

\end_inset 


\begin_inset LatexCommand \index{cd}

\end_inset 


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To move up one level in the terminal window type:
\layout LyX-Code

cd ..
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To move up two levels in the terminal window type:
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cd ../..
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To move down to the emc2/configs subdirectory in the terminal window type:
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cd emc2/configs
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Listing files in a directory
\begin_inset LatexCommand \index{Listing files in a directory}

\end_inset 


\begin_inset LatexCommand \index{dir}

\end_inset 


\begin_inset LatexCommand \index{ls}

\end_inset 


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To view a list of all the files and subdirectories in the terminal window
 type:
\layout LyX-Code

dir
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or 
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ls
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Finding a File
\begin_inset LatexCommand \index{Finding a File}

\end_inset 


\begin_inset LatexCommand \index{find}

\end_inset 


\layout Standard

The find command can be a bit confusing to a new Linux user.
 The basic syntax is:
\layout LyX-Code

find starting-directory parameters actions
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For example to find all the .ini files in your EMC2 directory you first need
 to use the pwd command to find out the directory.
 Open a new terminal window and type:
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pwd
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might return the following result
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/home/joe
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With this information put the command together like this:
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find /home/joe/emc2 -name *.ini -print
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The -name is the name of the file your looking for and the -print tells
 it to print out the result to the terminal window.
 The *.ini tells find to return all files that have the .ini extension.
 
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To find all the files in the directory named and all the subdirectories
 under that add the -L option to the find command like this:
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find -L /home/joe/emc2 -name *.ini -print
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Searching for Text
\begin_inset LatexCommand \index{Searching for Text}

\end_inset 


\begin_inset LatexCommand \index{grep}

\end_inset 


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grep -i -r 'text to search for' * 
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To find all the files that contain the 'text to search for' in the current
 directory and all the subdirectories below the current while ignoring the
 case.
 The -i is for ignore case and the -r is for recursive (include all subdirectori
es in the search).
 The * is a wild card for search all files.
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Hardware Problems
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Hardware Info
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To find out what hardware is connected to your motherboard in a terminal
 window type:
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lspci -v
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Monitor Resolution
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During installation Ubuntu attempts to detect the monitor settings.
 If this fails you are left with a generic monitor with a maximum resolution
 of 800x600.
 
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Instructions for fixing this are located here:
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\begin_inset LatexCommand \url{https://help.ubuntu.com/community/FixVideoResolutionHowto}

\end_inset 


\the_end