How to “merge” patterns in a single line

grepregular expressionsed

I am doing grep and sed and I get 2 lines of a file that I am interested in. How can I get these lines in a single line ending with the new line character?
Now I am getting:

pattern1  
pattern2

I would like to get pattern1 pattern2 \n

Best Answer

paste:

{...pipeline...} | paste -d " " - -

That says: "read a line from stdin (the first -), read another line from stdin (the second -), then join them with a space"

a bash-specific technique:

$ x=$(grep -o pattern. test.txt)
$ echo "$x"
pattern1
pattern2
$ mapfile -t <<< "$x"
$ echo "${MAPFILE[*]}"
pattern1 pattern2

ref: http://www.gnu.org/software/bash/manual/bashref.html#index-mapfile

Related Solutions

How to treat a file as a single line with grep to apply a regexp search pattern

Since a'r beat me to the sed solution, I'll just post the perl equivalent:

perl -ne 'print if/start/../end/'

It's a bit more verbose though.

Can Sed Replace New Line Characters?

With GNU sed and provided POSIXLY_CORRECT is not in the environment (for single-line input):

sed -i ':a;N;$!ba;s/\n/,/g' test.txt

From https://stackoverflow.com/questions/1251999/sed-how-can-i-replace-a-newline-n :

create a label via :a
append the current and next line to the pattern space via N
if we are before the last line, branch to the created label $!ba ($! means not to do it on the last line (as there should be one final newline)).
finally the substitution replaces every newline with a comma on the pattern space (which is the whole file).

Best Answer

Related Solutions

How to treat a file as a single line with grep to apply a regexp search pattern

Can Sed Replace New Line Characters?

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