How to Find Server Public IP Address in Linux Terminal

root@test:/var/log/nginx# wget -qO – icanhazip.com
www.xxx.yyy.zzz
root@test:/var/log/nginx# wget -qO- http://ipecho.net/plain | xargs echo
www.xxx.yyy.zzz
root@test:/var/log/nginx# wget -qO – icanhazip.com
www.xxx.yyy.zzz
root@test:/var/log/nginx# curl icanhazip.com
www.xxx.yyy.zzz
root@test:/var/log/nginx#

sed to play with data or parsing your text

To select all the lines starting from STARTING_PATTERN up to  blank line ^$ and then delete those lines.

# sed ‘/STARTING_PATTERN/,/^$/d’ filename

To edit files in place, use -i option.

# sed -i ‘/STARTING_PATTER/,/^$/d’ filename

Insert multiple lines into a file after specified pattern.

# sed ‘/cdef/r add.txt’ input.txt

# sed ‘/cdef/r add.txt’ input.txt

input.txt:
abcd
accd
cdef
line
web
add.txt:
line1
line2
line3
line4
Output :
abcd
accd
cdef
line1
line2
line3
line4
line
web

If you want to apply the changes in input.txt file. Then, use -i with sed.

# sed -i ‘/cdef/r add.txt’ input.txt

If you want to use a regex as an expression you have to use the -E tag with sed.

# sed -E ‘/RegexPattern/r add.txt’ input.txt