Join lines between a certain text pattern in Vim

:%s/\n\(\(A\.$\)\@!.*\)/\1/

Substitute a pattern matching:

newline,
a group containing of
1. not the string A. directly followed by end-of-line, then
2. any character until end of line

with:

everything matched except the starting newline (i.e. the group above),

and do this globally.

Daniel Andersson

Posted 2012-05-04T12:22:05.857

Reputation: 20 465

@DanielAndersson Is it possible to join the lines but to remove the break character A\.$ after joining the lines ? – Reman – 2015-11-10T22:18:36.607

1@Reman: The most straight-forward way I immediately think of is running a subsequent global pattern match like :%s/^A\.//. The method in the answer does not capture the ^A\. patterns themselves (rather their absence), so it cannot modify those strings in an obvious way. – Daniel Andersson – 2015-11-12T15:25:41.833

1Thanks. I have no idea how that thing works, but it seems to! I will have to dissect it carefully. I also found a work around by joining all the lines and then inserting a new line on "A." – vim noob – 2012-05-04T13:40:19.160

@vimnoob: See :help \@! in Vim for more info on that part. Otherwise it's straight forward, hopefully, with my explanation. A problem with your approach is that if "A." occurs in the text, though not as an isolated marker line, it will be split upon as if it were originally a marker. In practice it might not be a problem (I don't know what your "real" file looks like), but generically it can cause unwanted behavior if one is not aware of this. – Daniel Andersson – 2012-05-04T13:45:47.587

@vimnoob: I read my answer again, and in case you're not familiar with the :%s/// syntax: it's a "search and replace" syntax in Vim. : starts the command, % specifies the whole buffer as the range, s starts a substitution. / is the pattern delimiter (any other character can be used, but / is "standard"). The first / starts the search pattern, the second the replace pattern, and the third ends it. Trailing modifiers are available to specify case insensitivity, etc. \1 represents the grabbed group in the search pattern. :%s/foo/bar/ replaces foo with bar in the file. – Daniel Andersson – 2012-05-04T16:02:04.907

Thanks a lot for your help. I just need to research this @! part as I am familiar with the basic search replace and basic regexp. – vim noob – 2012-05-07T11:08:05.077

This is a great answer that I keep coming back to, but I have to confess that most of the time I just end up joining all of the lines and then splitting them. I just don't use \@! quite often enough to get proficient in its use. – Matt Parker – 2013-02-28T16:46:41.413

Yay, verily, and two tricks new to me, after the global anti-pattern match (v): the 'j' for join, and the '!' for join without adding a space. Thank you. – fortboise – 2014-11-20T18:30:06.450

@Miro wow! i salute you sir. if you could explain why it works then super!.. also i had to concatenate the lines with tab character in between... so what i did was to add a s/$/\t/g tab characterat end of every line before issuing above command.. any better way – ihightower – 2017-01-13T04:35:03.610

That does work! Nice. +1 – ZaSter – 2013-03-13T23:55:06.050

Join lines between a certain text pattern in Vim

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