在注释和空行之后，只在Makefile中插入一行

Question

I have a scenario where in I need to change thousands of Makefiles. 
I need to insert a line in Makefile and it should be the first effect code 
(Ignore comments and empty lines if found in the beginning of the file).

In the below example, I need to insert a line NEWLINE=1 in the Makefile.

Source Makefile
---------------

# copy right info
(empty line here).
# The file is mainly for ....
(empty file again here)
# note


all:
    gcc sample.c

Target Makefile
---------------

# copy right info
(empty line here).
# The file is mainly for ....
(empty file again here)
# note

NEWLINE= 1

all:
    gcc sample.c

Answer 1

awk的一种方式：

awk '/all:/{print "NEWLINE =1\n\n" $0;next}1' source > tmp && mv tmp source

或

sed（文件内替换）：

sed -i 's/all:/NEWLINE= 1\n\n&/' source

Answer 2

触摸〜/ tmp
chmod 777~ / tmp
echo sed -i \'$（grep -vnE“^ $ | ^＃”Makefile | head -1 | cut -f1 -d“ ：“）iNEWLINE = 1 \'Makefile＆gt; 〜/ TMP
＆安培;＆安培; 〜/ TMP