在sed中引入shell变量的四种方法 1.eval sed ’s/$a/$b/’ filename
2.sed "s/$a/$b/" filename
3.sed ’s/’$a’/’$b’/’ filename
4.sed s/$a/$b/ filename
2.sed "s/$a/$b/" filename
3.sed ’s/’$a’/’$b’/’ filename
4.sed s/$a/$b/ filename
2.sed "s/$a/$b/" filename
3.sed ’s/’$a’/’$b’/’ filename
4.sed s/$a/$b/ filename
2.sed "s/$a/$b/" filename
3.sed ’s/’$a’/’$b’/’ filename
4.sed s/$a/$b/ filename