Bash script to switch to the strongest wifi connection using nmcli

switch-wifi

#!/bin/bash
# switches to strongest known wifi connection using nmcli
set -euo pipefail

# returns "name:signal:in-use" in order of signal strength
conn_strength() {
  conns=()
  while IFS= read -r line; do
    conns+=("$line")
  done < <(nmcli -t -f name connection show)
  while read -r line;do
    name="${line%%:*}"
    for c in "${conns[@]}";do
      [[ "$name" == "$c" ]] && echo "$line"
    done
  done < <(nmcli -t -f ssid,signal,in-use dev wifi list)
  true
}

cur_name=
cur_strn=
max_name=
max_strn=
while read -r line;do
  name="${line%%:*}"
  strn="${line%:*}"
  strn="${strn#*:}"
  [[ -z "$max_name" ]] && max_name="$name" && max_strn="$strn"
  [[ "${line##*:}" == '*' ]] && cur_name="$name" && cur_strn="$strn"
done < <(conn_strength)

dif_strn=$(( max_strn-cur_strn ))
req_gain=20 # don't flap between similar-strength connections
if [[ "$max_name" != "$cur_name" ]] && [[ "$dif_strn" -ge "$req_gain" ]];then
  nmcli device wifi connect "$max_name"
fi
true