Ubuntu – How to find a word and add text after it in a .txt file

command linetext processing

How can I find a word (e.g. "/dn") in a text file and add on the next line another word (e.g. "/period")?

I'd like to execute it using MS DOS.

I mean this "/dn" (after /dn is space) is one word (not a fragment of the text, but the whole word–after /dn can be other word on the same line) which I want to find and then after it on the next new line, not replacing the other lines and other words. I mean create a new line between already existing lines.

For example, if I have this input file:

/dn
/name

I want this output:

/dn
/period
/name

and "/" symbol should be with dn, not without it.

Best Answer

1. Using `sed` append

If you want a completely new line with the word /period after each line containing /dn then use sed append:

sed '\:\dn:a/period' filename

the output for your sample would be:

/dn
/period
/name

1. Notes

:\dn: search for \dn
a/period append /period to the next line (a new line).

2. Search and append to the end of next line

If you want the /period at the end of the next line then use it like this:

sed ':/dn: { N; s:$:/period: }' filename

Here is a sample input:

/dn
/name

and the output:

/dn
/name /period

2. Notes

First we are searching for lines with /dn, then we add the /period at the end of ($) next line (N;).

Related Solutions

Ubuntu – Add words to a text file using a single terminal command (no editors)

I usually do this way when I am programming my script to do same what you are asking but programmatically.

echo "Hello you!" >> myfile.txt
echo "this is 2nd line text" >> file.txt
echo "last line!" >> file.txt

Voila! You got it. Important to note >> means adding new line to existing file meanwhile > just simply overwrite everything.

Ubuntu – Using sed to add text to a file before and after word

You can also process your list of words with the following perl command:

$ perl -ne 's/\s*$//; print "egrep -wi \047\|${_}\.\.nn\047 stats_all.txt > ${_}_frekvens.txt\n"' word_file.txt

Note that I'm using \047 to avoid escaping ' (single quote).

With a dummy word_file.txt:

foo
bar

The output is:

egrep -wi '\|foo\.\.nn' stats_all.txt > foo_frekvens.txt
egrep -wi '\|bar\.\.nn' stats_all.txt > bar_frekvens.txt