sed、awkパターン1行をコピーして次のパターン2行に貼り付ける

そしてsed：

sed '/^-country/{p;d};/^-city/{h;p;d};/^$/!{G;s/\n/ /}' test_file

複数行コメントで：

sed '
    /^-country/{p;d;}; # If found a country print and go to the next line
    /^-city/{h;p;d;};  # If found a city save the line, print and go to the next line
    /^$/!{G;s/\n/ /;}; # For any, non empty lines, get the one saved before and attach it to the current line.
' file

---

そしてawk：

awk '/^-city/{h = $0} NF && !/^-(country|city)/ {$0 = $0 " " h} 1' test

基本的には上記と同じですsed。

-city「save」で始まる行が見つかった場合。

次に、空でない各行（行または-country行-city自体ではない）について、以前に保存された行に関連付けられている現在の行を印刷します。

使用sed

$ sed '/^-city/h;/^-business/G;s/\n/ /' input_file
-country-france
-city-Paris, Marseille, Lyon, Toulouse, Nice, Nantes
-business-TotalEnergies -city-Paris, Marseille, Lyon, Toulouse, Nice, Nantes
-business-AXA -city-Paris, Marseille, Lyon, Toulouse, Nice, Nantes
-business-Carrefour -city-Paris, Marseille, Lyon, Toulouse, Nice, Nantes
-business-Crédit Agricole -city-Paris, Marseille, Lyon, Toulouse, Nice, Nantes
-business-Peugeot -city-Paris, Marseille, Lyon, Toulouse, Nice, Nantes
-business-BNP Paribas -city-Paris, Marseille, Lyon, Toulouse, Nice, Nantes

-country-india
-city-New Delhi, Bangalore, Mumbai, Chennai, Kolkata
-business-Reliance Industries Limited -city-New Delhi, Bangalore, Mumbai, Chennai, Kolkata
-business-State Bank of India -city-New Delhi, Bangalore, Mumbai, Chennai, Kolkata
-business-HDFC Bank -city-New Delhi, Bangalore, Mumbai, Chennai, Kolkata
-business-ICICI Bank -city-New Delhi, Bangalore, Mumbai, Chennai, Kolkata
-business-Tata Consultancy Services -city-New Delhi, Bangalore, Mumbai, Chennai, Kolkata
-business-Larsen & Toubro -city-New Delhi, Bangalore, Mumbai, Chennai, Kolkata

-country-japan
-city-Tokyo, Yokohama, Osaka, Nagoya, Sapporo, Fukuoka, Kobe
-business-Toyota Motor -city-Tokyo, Yokohama, Osaka, Nagoya, Sapporo, Fukuoka, Kobe
-business-Mitsubishi UFJ Financial -city-Tokyo, Yokohama, Osaka, Nagoya, Sapporo, Fukuoka, Kobe
-business-Softbank -city-Tokyo, Yokohama, Osaka, Nagoya, Sapporo, Fukuoka, Kobe
-business-Nippon Telegraph & Tel -city-Tokyo, Yokohama, Osaka, Nagoya, Sapporo, Fukuoka, Kobe

for nam in -country-france -country-india -country-japan; do cont=$(sed -n "/$nam/{n;p}"  gh.txt) ;echo $nam;sed -n "/$nam/{n;p}"  gh.txt;for linnum in $(awk -v nam="$nam" '$0 ~ nam,/^$/{print NR}' gh.txt |sed -e '1,2d' -e '/^$/d'); do awk -v linnum="$linnum" -v cont="$cont" 'NR==linnum {print $0,cont}' gh.txt|sed "/^ $cont/d";done;done

出力

-country-france
-city-Paris, Marseille, Lyon, Toulouse, Nice, Nantes
-business-TotalEnergies -city-Paris, Marseille, Lyon, Toulouse, Nice, Nantes
-business-AXA -city-Paris, Marseille, Lyon, Toulouse, Nice, Nantes
-business-Carrefour -city-Paris, Marseille, Lyon, Toulouse, Nice, Nantes
-business-Crédit Agricole -city-Paris, Marseille, Lyon, Toulouse, Nice, Nantes
-business-Peugeot -city-Paris, Marseille, Lyon, Toulouse, Nice, Nantes
-business-BNP Paribas -city-Paris, Marseille, Lyon, Toulouse, Nice, Nantes
-country-india
-city-New Delhi, Bangalore, Mumbai, Chennai, Kolkata
-business-Reliance Industries Limited -city-New Delhi, Bangalore, Mumbai, Chennai, Kolkata
-business-State Bank of India -city-New Delhi, Bangalore, Mumbai, Chennai, Kolkata
-business-HDFC Bank -city-New Delhi, Bangalore, Mumbai, Chennai, Kolkata
-business-ICICI Bank -city-New Delhi, Bangalore, Mumbai, Chennai, Kolkata
-business-Tata Consultancy Services -city-New Delhi, Bangalore, Mumbai, Chennai, Kolkata
-business-Larsen & Toubro -city-New Delhi, Bangalore, Mumbai, Chennai, Kolkata
-country-japan
-city-Tokyo, Yokohama, Osaka, Nagoya, Sapporo, Fukuoka, Kobe
-business-Toyota Motor -city-Tokyo, Yokohama, Osaka, Nagoya, Sapporo, Fukuoka, Kobe
-business-Mitsubishi UFJ Financial -city-Tokyo, Yokohama, Osaka, Nagoya, Sapporo, Fukuoka, Kobe
-business-Softbank -city-Tokyo, Yokohama, Osaka, Nagoya, Sapporo, Fukuoka, Kobe
-business-Nippon Telegraph & Tel -city-Tokyo, Yokohama, Osaka, Nagoya, Sapporo, Fukuoka, Kobe