sed command to replace a word from one file with entire line of another file

Question

I want to use the sed command (or something that works) to replace a word in a template file with a word in a line of another file.

As an example I have a file with a list of words, each word is in a different line and I want to use sed to take the first word (which is in the first line) and put it in another file where the word "value1" is written. I thought that with this post I could be able to do it, but I can't figure it out.

Graphic example:

File A:

Maria
Albert
Toni
Henry
Tom

File B:

The name of the student is: value1

Expected output for line 3:

The name of the student is: Toni

I want to be able to move one of the names from file A to file B where value1 is placed. And I want to do it multiple times.

I just edited the question with an example input and output. — Enrique Torelló Perelló, Apr 18 '18 at 09:34
Does value1 always occur one and only one time in the template? — Stéphane Chazelas, Apr 18 '18 at 09:37
yes, value1 occurs only 1 time, I will use different value names for every word I have to replace. — Enrique Torelló Perelló, Apr 18 '18 at 09:39
The template is not always a single line, it was just for the example. The template file has multiple lines with multiple values to replace from the listing file A. — Enrique Torelló Perelló, Apr 18 '18 at 09:40
You mean there's potentially a value2, value3... ? How are the corresponding entries stored in fileA? — Stéphane Chazelas, Apr 18 '18 at 09:43
yes, there will be value2, value3, valueN... The entries are stored line by line, like a list. — Enrique Torelló Perelló, Apr 18 '18 at 09:59
@EnriqueTorellóPerelló, and how should value1, value2 and value3 be distributed along 5 input lines? — RomanPerekhrest, Apr 18 '18 at 10:11
@RomanPerekhrest They can be distributed anywhere in the text, I just need to take a word from the list (file A) and substitute it for one of the selected values in file B. — Enrique Torelló Perelló, Apr 18 '18 at 10:16
Please expand your example to cover several values and lines. I still don't understand why value1 is douns on line 3. — Philippos, Apr 18 '18 at 11:45
Why not use printf formats instead of your own format? Example ' The name of the student is %s', then you would not need to do the search and replace of value1 which @Stéphane Chazelas does in his perl script. — Raphael Ahrens, Apr 20 '18 at 06:36

Stéphane Chazelas · Answer 1 · 2018-04-18T10:22:50.590

1

I'd use perl:

perl -ne '
  BEGIN{
    local $/ = undef;
    $template = <STDIN>; # slurp file B in
  }
  chomp;
  print $template =~ s/\bvalue1\b/$_/gr' fileA < fileB

If your version of perl is too old to support the r substitute flag, you can use a temporary variable:

perl -ne '
  BEGIN{
    local $/ = undef;
    $template = <STDIN>; # slurp file B in
  }
  chomp;
  ($out = $template) =~ s/\bvalue1\b/$_/g;
  print $out' fileA < fileB

edited Apr 18 '18 at 10:22

answered Apr 18 '18 at 09:45

Stéphane Chazelas

544,893

It gives me a compilation error and I never used perl... :/ Any suggestions? – Enrique Torelló Perelló Apr 18 '18 at 10:05
@EnriqueTorellóPerelló, possibly, you have an old version of perl before the r flag was added. – Stéphane Chazelas Apr 18 '18 at 10:15
where do I specify the line from file A to replace in file B? I suppose that value1 is the value from file B to be replaced. Right? – Enrique Torelló Perelló Apr 18 '18 at 10:41
@EnriqueTorellóPerelló, that answer answers your question as currently stated in the body of your question, the additional comments to your question seem to suggest a different question. I've given up trying to guess what you actually want to do. You should edit your question with a more relevant example. – Stéphane Chazelas Apr 18 '18 at 11:53

sed command to replace a word from one file with entire line of another file

1 Answers1