Linux -- Examples of Everyday Linux Commands

Last updated: 6/16/2002; 10:20:39 AM

Marketing 101. Consulting 101. PHP Consulting. Random geeky stuff. I Blog Therefore I Am.

or "Scott's Ongoing Linux Struggle"

Co Author: Kjartan Mannes

I have been using Unix (SunOS) since 1986 on Sun 2s.  Despite this I find myself constantly asking stupid Linux questions whenever I encounter a more knowledgable Unix admin.  For me the problem isn't lack of understanding – it's poor memory.  This document gives examples for common Linux commands like "how do I shut down Apache", "how do I view the last 100 entries in an error log" and so on.  It's arranged topically by section.  And, where I felt appropriate, I added general Linux advice like the section on GUI Admin Tools.

My heartfelt thanks go out to Kjartan who suffered through my silly questions with not a single trace of the all too common Unix Sys Admin arrogance or "Stupid user, how dare you ask me that.  Off with your head!".

GUI Admin Tools

If you need a GUI admin tool for remote Linux administration then run, do not want, to Webmin.  www.webmin.com.  Highly recommended. 

Editors

There are a plethora of Linux editors.  Tons.  Even more than tons.  There are three editors that are almost always present on a given Linux box:

• VI
• Emacs
• Pico

Editors are like religion and I don't go near religious debate.

Chown and Chmod

chown and chmod are the two Linux commands that you use most frequently for web development, particularly if you are a Perl programmer.  chown changes the ownership of a file while chmod changes it's "mode" i.e. read, write, execute, etc.

User Management

MySQL

Question: How do I restart MySQL?

It's either of these two commands (determine which by looking at the ps example below):

• mysqld
• safe-mysqld

Question: How do I shutdown MySQL?

Use: mysqladmin shutdown

Question: How do I check if MySQL is still running?

You'll get back something like this:

mysql 5381 0.0 0.5 108260 6100 ? S May21 0:00 /usr/sbin/mysqldmysql 5382 0.0 0.5 108260 6100 ? S May21 0:05 /usr/sbin/mysqldmysql 5383 0.0 0.5 108260 6100 ? S May21 0:00 /usr/sbin/mysqldmysql 25949 0.0 0.5 108260 6100 ? S May24 0:58 /usr/sbin/mysqldmysql 27913 0.0 0.5 108260 6100 ? S May26 0:11 /usr/sbin/mysqld

Or you can use just mysql and check from the user interface.  I prefer ps myself.

Client Side Errors that Make you Think it's Server Side

Two things:

Just as a general comment

es (05:41:25 AM): MSIE in its infinate wisdom repots dns errors when servers have in fact crashed

CVS

kjartanmannes (05:57:38 AM): try a cvs up
kjartanmannes (05:57:44 AM): maybe something is confliting
fuzzygroup (05:57:54 AM): ok.
fuzzygroup (05:58:11 AM): can I get the exact syntax so I don't muck it up (I'll learn over time, I promise)
fuzzygroup (05:59:41 AM): mvr mind
fuzzygroup (05:59:42 AM): found it
kjartanmannes (05:59:44 AM): cvs update
kjartanmannes (05:59:45 AM):

Apache

fuzzygroup (05:42:07 AM): Apache logs are most recent last, so is there a simple command line to get the last 100 lines?
kjartanmannes (05:42:30 AM): tail -100 logfile

PHP

kjartanmannes (06:11:57 AM): its almost as if your PHP process crashes while parsing the page
fuzzygroup (06:12:26 AM): how do I check for a php crash?
kjartanmannes (06:12:46 AM): you have the command line interface running?
kjartanmannes (06:12:53 AM): IE: can you access php from the shell
fuzzygroup (06:13:03 AM): Not sure. will phpinfo tell me?
fuzzygroup (06:13:33 AM): if so http://www.inboxbuddy.com/version.php has it.
kjartanmannes (06:13:51 AM): just try typing php
kjartanmannes (06:14:03 AM): if it gives you command not found you are outta luck

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