sed -i

• https://manpages.ubuntu.com/manpages/noble/en/man1/sed.1.html

-i tells sed to modify the file in place.

-i[SUFFIX], --in-place[=SUFFIX] edit files in place (makes backup if SUFFIX supplied)

sudo sed -i '/#net.ipv4.ip_forward=1/s/^#//g' /etc/sysctl.conf

Related

.BAK
gsed -i
Add line

See also

• sed, gsed, -n, -i, Ansible: replace, append, Chef: Editing a file‎‎, lineinfile