使用sed在文本文件中移动匹配行

Question

I am trying to follow the post

How to move specified line in file to other place with regexp match (bash script)?

to my example file

asdasd0
-SRC_OUT_DIR = /a/b/c/d/e/f/g/h
asdasd2
asdasd3
asdasd4
DEFAULTS {
asdasd6

The final output should look like

asdasd0
asdasd2
asdasd3
asdasd4
DEFAULTS {
-SRC_OUT_DIR = /a/b/c/d/e/f/g/h
asdasd6

I have tried the following

sed "/-SRC_OUT_DIR.*/d;/DEFAULTS { /a"$(sed -n '/-SRC_OUT_DIR.*/p' test.txt)  test.txt`

but it is not working. I get the following output

sed:can't read =: No such file or directory
sed:can't read "/a/b/c/d/e/f/g": No such file or directory
asdasd0
asdasd2
asdasd3
asdasd4
DEFAULTS {
-SRC_OUT_DIR
asdasd6

I am also wondering why can't I use \\1 , \\2 to print the line that needs to be moved. I tried that but it prints nothing. How would I write a sed command if I need to move multiple matching lines to different places in the file?

Answer 1

You could store the matching line in the hold space, delete it and then append the hold space to the line after which you want to insert:

$ sed '/^-SRC_OUT_DIR/{h;d;};/^DEFAULTS {/G' infile
asdasd0
asdasd2
asdasd3
asdasd4
DEFAULTS {
-SRC_OUT_DIR = /a/b/c/d/e/f/g/h
asdasd6

Answer 2

While you ask a sed solution I would propose to use awk for this. Using an ugly nesting of a multitude of sed commands is not really recommended. Especially because you read your file twice.

Here is an awk

awk '/SRC_OUT_DIR/{t=$0;next}1;/DEFAULTS/{print t}' file

How does it work?

awk will read your file line by line. Per line, it will do the following three commands one after the other:

1. /SRC_OUT_DIR/{t=$0;next} : if the line contains a substring matching SRC_OUT_DIR , then store the line in a variable t and move to the next line (don't execute 2 and 3)
2. 1 : default action: print the line
3. /DEFAULTS/{print t} : if the current line contains the substring DEFAULTS , print the line stored in variable t

If you have multiple lines to move (this only moves downwards):

awk '/pattern1/ {t[1]=$0;next}
     /pattern2/ {t[2]=$0;next}
     /pattern3/ {t[3]=$0;next}
     /target3/ { print t[3] }
     1
     /target1/ { print t[1] }
     /target2/ { print t[2] }' file

note that pattern3 will be printed before target3 .