Firstly, make sure you have enough space on your drive. At CD quality, 44.1 Khz 16 Bit stereo, 1 minute takes nearly 5 Mb.
I normally record at DAT quality, which is 48 Khz 16 Bit stereo.
Using wavrec I use the following syntax:
/usr/local/bin/wavrec -t 60 -s 48000 -S /mnt/mp3/temp.wav
The first part is an explicit path to wavrec. The '-t 60' specifies the length of time to record for, in seconds.
The third option, -s 48000 refers to the sample rate in bits/sec. (48000 is the rate for DAT, 44100 is CD)
The last option is the path to the output file.
To see the full set of options, run waverec -help, or see it's man page.
This will produce your WAV file Next you will need to encode it into MP3 format.
Use bladdenc with the following command line.
/usr/local/bin/bladeenc [source file] [destination file] -br 256000
The -br option sets the bit rate, in this case I've set the rate to the maximum rate of 256k bits/s. The path to bladeenc may also be different on your system to the one I've used in my example.
To see the full set of options, run bladeenc -help, actually this is an invalid option, but will display the list of options.