试图在sed或awk中使用变量

Question

I have 2 separate text files, each in the same exact format. I can grep FILE1.txt for a specific search term and output the line numbers of every match. The line numbers are outputted in numeric order to a file or a variable.

I want use each line number and print that line from FILE2.txt in numeric order to a single OUTPUT.txt . Does anyone know a way, using awk or sed to do this?

I have a string variable $linenumbers with values of 25 26 27 28.

I use the following command:

for i in $linenumbers; do sed -n "/$I/p" $i test_read2.fastq >> test.fastq; done.

I get errors of

sed: can't read 25: No such file or directory

sed: can't read 26: No such file or directory

sed: can't read 27: No such file or directory

sed: can't read 28: No such file or directory

If I do this sed command one by one, I can pull line number 25, 26, 27 and 28 from the file and print it to file using the following command;

sed -n "25p" test_read2.fastq >> test.fastq

I want to replace "25p" with variable so it pulls out multiple lines (25,26,27,28) from the file without doing this one by one...

Answer 1

Try this:

grep -n interesting FILE1.txt | cut -d: -f1 | while read l
do
   sed -n "$l p" FILE2.txt
done

Example:

$ cat FILE1.txt 
foo
bar
baz
$ cat FILE2.txt 
qux
quux
quuux
$ grep -n bar FILE1.txt | cut -d: -f1 | while read l; do sed -n "$l p" FILE2.txt; done
quux

Answer 2

Not sure what exactly you want to do. If you want to print the lines of file which are defined in lines you could do awk 'NR==FNR{a[$0];next}FNR in a' lines file

test:

$ cat lines
1
3
7
$ cat file
a
b
c
d
e
f
g

$ awk 'NR==FNR{a[$0];next}FNR in a' lines file
a
c
g

Answer 3

sed -n "` grep -n 'Yourpattern' File1.txt | sed 's/:.*/p/'`" File2.txt

是carefful在替代和（双）报价YourPattern