search for inverse of pattern and join with the line before it
 

Let's say I have:

And I need to turn it into:

I hacked together some sed that will find lines that start with a number between 1 and 5 digits, followed by a dot and one or more spaces and replace newline at the end with a space to join each line containing this pattern with the line that follows:

And also sed that will find lines that start with "text" and join each with the preceding line:

But I cannot figure out how to find lines not matching a pattern (inverse match, like "grep -v") and then append each to the preceding line.

Something like the following (which doesn't work):

Any way to do this with sed (or awk, or something else)?

try this out, It worked for me

I don't grasp what this does or how it fits with the question....???

that was formulated according to the output he wants using the sample input. BUT it does not check for the digits and such because the output OP wants all have alphabets. Hence my suggestion. Of course, if there are more variation of input then there will be a need to do more thorough check like what colucix did.

ghostdog, the input has lines that contain only the year which has to be appended to the previous lines. Only the output has alphabets in every line. In my code I just checked the first number immediately followed by a dot, as suggested by the OP.

awk, or the Perl programming language, would be an appropriate tool for this, because the task at hand is expressed algorithmically.

(1) Initialize a line-buffer to an empty string.

(2) While not end-of-file, read another newline-delimited string and append it to the buffer.

(3) Look within the buffer for "some text, and a date." If you find that, remove it from the head of the buffer and output it. Keep the tail of the string in the buffer.

(4) Repeat step (3) until no more matches can be found.

(5) When you reach the end-of-file, don't forget what's still in the buffer (if anything). In this case I don't think you intend to do anything with it.

This algorithm suggests itself because, in the data you provide, I see that newlines can appear anywhere in a date, which is nevertheless seen as one.

The two tools that I spoke of are "power tools" for doing this kind of string-manipulation and file parsing.

thanks. i missed the year to append to previous.

This uses GNU sed:-
All of the lines are appended one at a time in the pattern space separated by \n. If the start of the latest line in doesn't match the number pattern then the 's' command replaces the last '\n' in the pattern space with a space.
It can join a continuous run of lines which don't start with the number pattern.

Thanks a lot, everyone, this is some great stuff!

Kenhelm, this is great and works perfectly, but I don't fully understand it. Here's what I see, please correct me.. :-P

1. Tells sed to expect extended regexp
2. Creates a label to return to later
3. Appends the next line of input into the pattern space
4. Pattern starts with newline
5. Pattern to match
6. ?
7. Matches till the end of line
8. Negates previous expression
9. Substitutes
10. Anything followed by a newline?
11. Replaces with ?? <-- Edit: "\1" means first saved substring
12. Returns to label

Thanks again!

Ghostdog, this works perfectly, but could you explain how it works?

Cheers!

colucix, thanks much, sorry for being dense, but how do I run this? Running it from the shell runs without error, but doesn't work.

PMP, thanks, that works great. Clever workaround to not have to bother with holding stuff in the buffer.. I see you're using that \1 at the end, too.. Gotta figure out what that means..