Question

I’m a beginner to sed. I know that it’s possible to apply a command (or a set of commands) to a certain range of lines like so

sed '/[begin]/,/[end]/ [some command]'

where [begin] is a regular expression that designates the beginning line of the range and [end] is a regular expression that designates the ending line of the range (but is included in the range).

I’m trying to use this to specify a range of lines in a file and join them all into one line. Here’s my best try, which didn’t work:

sed '/[begin]/,/[end]/ {
N
s/\n//
}
'

I’m able to select the set of lines I want without any problem, but I just can’t seem to merge them all into one line. If anyone could point me in the right direction, I would be really grateful.

Answer 1

One way using GNU sed:

sed -n '/begin/,/end/ { H;g; s/^\n//; /end/s/\n/ /gp }' file.txt