# If you'd like to omit non-matching lines from the result; add ';d' to the end of the expression.
sed -E 's/^(.+)(?<!\\)((?:\\\\)*)(\!\=|(?<!\!|\<|\>)=|\<\=|\>\=)(.+)$/[$1$2] $3 [$4]/gm;t' <<< "name=toto
tat\=a
bla\bla=tor
blood\\=orange
wrong\\\=cops
right\\\\=escaping
extrem\\\\\=slash
hoho\\\\\\=ho
is\\\\\\\=magic
noend=
dou=bl=equal
ma\=tche!=operation
is\\!=not
is<=inferior
is>=superior
tha>t=isno<t
-----
^(.+)((?<!\\)=)(.+)$"
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for SED, please visit: https://www.gnu.org/software/sed/manual/html_node/The-_0022s_0022-Command.html