a1667203

command

% cat sedtest.txt
EXEC-PREFIX="./_install"
PREFIX="./_install"
% sed '1,$s;PREFIX="\./_install";PREFIX="/usr/local/bin";' sedtest.txt    #1
EXEC-PREFIX="/usr/local/bin"
PREFIX="/usr/local/bin"
% sed '1,$s;PREFIX=.*;PREFIX="/usr/local/bin";' sedtest.txt               #2
EXEC-PREFIX="/usr/local/bin"
PREFIX="/usr/local/bin"
% sed '1,$s;^PREFIX=.*;PREFIX="/usr/local/bin";' sedtest.txt              #3
EXEC-PREFIX="./_install"
PREFIX="/usr/local/bin"
% 

1.PREFIX="./_install"をPREFIX="/usr/local/bin"に置換
2.PREFIX=から始まる任意の文字列をFREFIX="/usr/local/bin"に置換
3.PREFIX=から始まる行をFREFIX="/usr/local/bin"に置換

note

cf.
% man sed