To start a ppp interface (dial-up connection), I normally use kppp available under the KDE "K" menu (or by typing kppp in an X-terminal).
ifdown interface_name
(/sbin/ifdown to run it as a user). Shut down the network interface. E.g.: ifdown ppp0 Also, see the previous command.
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netstat | more
Displays a lot (too much?) information on the status of your network.
/usr/sbin/mtr --gtk
(as root, in X windows if you wish the nice gtk-based interface). Network diagnostic tool combining the capabilities of traceroute and ping. Comes with RH7.0.
nmap ip_number
Map the ports on the machine with ip_number. REALLY useful to establish the security of your network configuration as you can see the opened ports. nmap is included on the RH7.0 "Linux PowerTools" CD, as is a convenient GUI front end, "nmapfe". nmap can also do operating system
"fingerprinting". Normally, people (and their ISPs) don’t like their computer ports being scanned (they view it as possbily probing before an attack) so they may complain if they find out--learn how to use nmap on your own computers else you will soon hear from your ISP (the complaints will go to them).
How do I know this?
ethereal
(as root, in Xterminal) Network analyzer--view the network trafic going through your computer.
Included on the RH7.0 "Linux PowerTools" CD. Using ethereal may be unethical in some situations, and unauthorized use in the workplace could be a fireable offence.
5.17 Music-related commands
cdplay play 1
Play the first track from a audio CD. Use cdplay to play the whole CD. Use cdplay stop when had enough.
eject
Get a free coffee cup holder :))). (Eject the CD ROM tray). This command defaults to the cdrom, but could be used to eject other removable media by specifying the mount point or device. E.g., I can eject the zipdisk from the zipdrive (as root) using: eject /dev/sda4
play my_file.wav
Play a wave file.
rec my_file.wav
Record a wave file from my microphone.
mpg123 my_file.mp3
Play an mp3 file.
mpg123 -w my_file.wav my_file.mp3
Create a wave audio file from an mp3 audio file. Useful if you wanted to write a regular audio CD
from mp3s--you have to convert the mp3s to the *.wav format first. Don’t be surprised the conversion is slow--decompressing mp3s is very processor intensive.
xmms
(in X terminal) Nice GUI mp3 player.
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freeamp
(in X terminal) Another GUI mp3 player.
lame input_file output_file
MP3 encoder.
knapster
(in X terminal) Start the program to downoload mp3 files that other users of napster have displayed for downloading. You may share your mp3s too. Really cool, while it lasts. Gnutella and FreeNet will soon replace them->it gets even cooler.
cdparanoia -B "1-"
(CD ripper) Read the contents of an audio CD and save it into wavefiles in the current directories, one track per wavefile. The "1-" means "from track 1 to the last". -B forces putting each track into a separate file.
playmidi my_file.mid
Play a midi file. playmidi -r my_file.mid will display text mode effects on the screen.
sox audio_file another_format_audio_file
(="SOund eXchange") Convert from almost any audio file format to another (but not mp3s). See man sox for the list of supported audio file formats (many). sox also lets you add special effects to your sound file.
kscd
(in X terminal) CD player.
kmidi
(in X terminal) MIDI player.
kmid
(in X terminal) MIDI/caraoke player.
kmix
(in X terminal) Sound mixer.
studio
(in Xterminal) Sound Studio--edit sound files, add effects, etc. Available on the on the PowerTools CD, RH7.x.
extace
(in Xterminal) Sound visualization utility.
festival --tts my_file.txt
Say the content of the my_file.txt file (ascii text). "festival" is a speach synthesizer that comes on the RedHat 7.0 "Linux PowerTools" CD. To say something from the command line, you need to start up "festival" and then, at the "festival>" prompt, type the appropriate command (scheme interpreter), as in this example (bold represents the prompt):
festival
festival> (SayText "good dog, really good dog")
festival> (quit)
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5.18 Graphics-related commands
kghostview my_file.ps