правка текста

<<EOF sed 's/$/:IPv4/'
0.0.0.0
1.1.1.1
2.2.2.2
EOF

vodka@vodka-PC:/tmp$ cat ./1.txt
0.0.0.0
1.1.1.1
2.2.2.2
3.3.3.3
4.4.4.4
5.5.5.5
6.6.6.6
7.7.7.7
8.8.8.8
9.9.9.9
vodka@vodka-PC:/tmp$ sed -z 's/\n/:IPv4\n/g' ./1.txt 
0.0.0.0:IPv4
1.1.1.1:IPv4
2.2.2.2:IPv4
3.3.3.3:IPv4
4.4.4.4:IPv4
5.5.5.5:IPv4
6.6.6.6:IPv4
7.7.7.7:IPv4
8.8.8.8:IPv4
9.9.9.9:IPv4