How to insert the content of a file into another file (if regexp) in perl/shell

Question

File1 Contents:

line1-file1      "1" 
line2-file1      "2"
line3-file1      "3" 
line4-file1      "4" 

File2 Contents:

line1-file2     "25"  
line2-file2     "24"  
Pointer-file2   "23"  
line4-file2     "22" 
line5-file2     "21"

After the execution of perl/shell script,

File 2 content should become

line1-file2     "25"  
line2-file2     "24"  
Pointer-file2   "23" 
line1-file1      "1" 
line2-file1      "2"
line3-file1      "3" 
line4-file1      "4"  
line4-file2     "22" 
line5-file2     "21"

i.e Paste the contents of file 1 in file 2 after that "Pointer" containing line.

Thanks

Also asked at [Unix.SE](http://unix.stackexchange.com/q/32908/4667) — glenn jackman, Feb 28 '12 at 11:38
Also http://stackoverflow.com/questions/11243102/using-sed-to-insert-file-content — Necreaux, May 10 '16 at 18:50
I'm voting to close this question as off-topic because it is a crosspost. — peterh, Nov 15 '17 at 02:42

kev · Accepted Answer · 2012-02-28T07:51:27.510

8

Use the r command in sed to append text file:

$ sed -i '/Pointer-file2/r file1' file2

$ cat file2
line1-file2     "25"
line2-file2     "24"
Pointer-file2   "23"
line1-file1      "1"
line2-file1      "2"
line3-file1      "3"
line4-file1      "4"
line4-file2     "22"
line5-file2     "21"

Use the r command in ed to insert text file:

$ echo -e '/Pointer/-1r file1\n%w' | ed -s file2

$ cat file2
line1-file2     "25"
line2-file2     "24"
line1-file1      "1"
line2-file1      "2"
line3-file1      "3"
line4-file1      "4"
Pointer-file2   "23"
line4-file2     "22"
line5-file2     "21"

edited Feb 28 '12 at 07:51

answered Feb 28 '12 at 05:40

kev

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Sir, How to do the same if we want to paste before that "pointer" containing line – user1228191 Feb 28 '12 at 06:04
@user1228191 Actually, it's **`r`**, the slash belongs to **`/pattern/`** – kev Feb 28 '12 at 07:41
yes kev, that was a typo error!! Is there anything like `r` command to paste it before that **pointer** containing line – user1228191 Feb 28 '12 at 07:55
How would one modify this such that the file is inserted before every occurrence of Pointer in file2? – shaz Aug 16 '16 at 16:48

score 4 · Answer 2 · answered Feb 28 '12 at 06:17

I'd use Tie::File. Roughly,

use Tie::File;
tie my @a, 'Tie::File', 'File2' or die;
tie my @b, 'Tie::File', 'File1' or die;
for (0..$#a) {
  if (/^Pointer-file2/) {
    splice @a, $_, 0, @b;
    last
  }
}

It's longer than that use of sed, but it should also be easier to see how you'd alter this for slightly different tasks.

How to insert the content of a file into another file (if regexp) in perl/shell

2 Answers2