Turn the power on with the power button and hold Command-Option-O-F — this will boot you into open firmware. Now type eject cd and wait until the CD pops out. Type mac-boot to reboot.
On May 9, 2005, In Apple OS X, By Brad
On May 5, 2005, In Linux, By Brad
This post outlines a couple of commonly used Linux commands.
man – command used to display manual pages for specific commands (e.g., “man ls”). Man pages are your friend!
ls – similar to the DOS dir command. It lists directory contents. Try “ls -al” for a detailed directory listing.
cd – change directory. “cd ~” will take you to your home directory.
rm – used for deleting files and folders. Similar to the DOS del command.
mv – move or rename a file
cp – copy a file
ps – shows running processes. “ps aux” shows a good amount of info.
startx – Starts X windows if run from the system console (assuming it is configured).
pwd – displays your “present working directory” or current directory.
exit – closes a shell session or logs you out of the console.
./file – executes the file located in the current directory. The current directory is represented by “./”. This is useful when you want to execute a command or script that isn’t located within the system path.
shutdown -r now – reboot the system NOW.
shutdown -h now – halt the system NOW.
vi – starts up a popular but not very user-friendly editor. vi is a very powerful editor but it takes a little getting used to.
df – shows free disk space on all volumes
free – shows free memory. Use the “-m” parameter to show memory in MB.
du – shows directory usage in terms of space for current directory and all subdirectories.
top – shows system processes. Hit “q” to exit.
uptime – shows uptime and system load statistics
cat – concatenate files and print on the standard output. To display a text file on the screen, type “cat filename”
There are many more commands; too many to cover here. However, the commands listed above should be enough to allow you to navigate around a linux system.
A couple more notes:
- “.” represents the current directory.
- “..” represents the parent directory (e.g., “cd ../images” will change directory into the images folder in the parent directory).
- “~” represents your home directory (e.g., /home/jsmith). The “~” can be used in path representations such as “cd ~/public_html” which is the same as typing “cd /home/jsmith/public_html”.
On May 4, 2005, In MySQL, By Brad
The following steps can be executed as a non privileged user on the server, however, the username and password you use with the commands needs to be a database user that has r/w privileges within MySQL (think “sa” account for Microsoft SQL Server).
1. Export the database to a SQL file.
[user@host]$ mysqldump --opt --user=dbuser \
--password database > dumpfile.sql
2. Edit the dump file and put these lines at the beginning:
SET AUTOCOMMIT = 0;
SET FOREIGN_KEY_CHECKS=0;
3. Put these lines at the end:
SET FOREIGN_KEY_CHECKS = 1;
COMMIT;
SET AUTOCOMMIT = 1;
4. Import the database SQL file into MySQL. This will overwrite the contents of the current database.
[user@host]$ mysql --user=dbuser \
--password database < dumpfile.sql
Click here for a good shell script that automates the backup of MySQL databases. Version 2.5 is available here for download.