Add instructions for addingnew SSID for headless pit

addWifiHeadless.md

@@ -0,0 +1,84 @@
+With a bit of prep work, this can be achieved relatively simply
+
+First, create a file, `addwlan.sh`, in the boot partition - contents at the end of the answer
+
+in `cmdline.txt` on the boot sector you'll want to add (it's a single line by the way)
+
+    systemd.run=/boot/firmware/addwlan.sh systemd.run_success_action=reboot systemd.unit=kernel-command-line.target
+
+To the end of the line in `cmdline.txt`
+
+It should end up looking like
+
+    console=tty1 root=PARTUUID=****** rootfstype=ext4 fsck.repair=yes rootwait cfg80211.ieee80211_regdom=** systemd.run=/boot/firmware/addwlan.sh systemd.run_success_action=reboot systemd.unit=kernel-command-line.target
+
+The \*\*\* will be something unique to your situation, DO NOT CHANGE
+
+This is the contents of addwlan.sh in the boot partition:
+
+Note:
+
+* NAME: this will be the name of the `.nmconnection` file created and its `ID` \- note that `UUID` is generated
+* SSID: the SSID you want to connect to
+* PRIORITY: use negative for higher priority - FYI: default for wifi connections is zero
+* HIDDEN: set to `true` if it is hidden
+* PASS: leave blank for open AP
+* PLAIN: set to 1 if you add the password in plain text, the code will convert it to a passphrase using `wpa_passphrase` otherwise use `PLAIN=0`
+
+---
+
+    #!/bin/bash
+    
+    # ---- configure connection - change as appropriate
+    NAME=<connectionName>
+    SSID=<SSID>
+    PRIORITY=0
+    HIDDEN=[true|false]
+    PASS=<password>
+    PLAIN=1
+    # ---- end configure connection
+    
+    CONNFILE=/etc/NetworkManager/system-connections/${NAME}.nmconnection
+    UUID=$(uuid -v4)
+    
+    if [ ! -z "${PASS}"]; then
+        if [ $PLAIN -eq 1 ]; then
+            PSK="$(wpa_passphrase ${SSID} ${PASS} | grep -T "psk" | grep -v '"' | cut -d= -f 2)"
+        else
+            PSK="${PASS}"
+        fi
+    fi
+    
+    cat <<- EOF >${CONNFILE}
+    [connection]
+    id=${NAME}
+    uuid=${UUID}
+    type=wifi
+    autoconnect-priority=${PRIORITY}
+    [wifi]
+    mode=infrastructure
+    ssid=${SSID}
+    hidden=${HIDDEN}
+    [ipv4]
+    dns-priority=100
+    method=auto
+    [ipv6]
+    dns-priority=50
+    addr-gen-mode=default
+    method=auto
+    [proxy]
+    EOF
+    if [ ! -z "${PASS}" ]; then
+        cat <<- EOF >>${CONNFILE}
+    [wifi-security]
+    key-mgmt=wpa-psk
+    psk=${PSK}
+    EOF
+    fi
+    chmod 600 ${CONNFILE}
+    sed -i 's| systemd.run=/boot/firmware/addwlan.sh.*||g' /boot/firmware/cmdline.txt
+    exit 0
+
+Put the SD card back in the pi and reboot. Note, there will be a second reboot once the config is written, so be patient.
+
+Tested to work on Pi 4 running latest Raspberry Pi Bookworm - should work if you installed 64bit bookworm or trixie - no guarantees if you went for 32 bit