sed -i "s/替换前内容/替换后的内容/g" b.txt
例： sed -i "s/basedir/BBB/g" b.txt
例：带路径的替换 sed -i "s#basedir=#basedir=/usr/local/mysql#g" b.txt
sed -i "s#basedir=#basedir=/usr/local/mysql#g" b.txt
sed -i "s/替换前内容/替换后的内容/g" b.txt
例： sed -i "s/basedir/BBB/g" b.txt
例：带路径的替换 sed -i "s#basedir=#basedir=/usr/local/mysql#g" b.txt
sed -i "s#basedir=#basedir=/usr/local/mysql#g" b.txt
