Swap the appearance order of two lines if needed.
in [Shell]
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From: Hongyi Zhao on 25 Nov 2009 21:33 On Tue, 24 Nov 2009 12:22:17 -0800 (PST), Rakesh Sharma <sharma__r(a)hotmail.com> wrote: >Provided there's atleast one line between line_a & line_b we can do >this: In my case, the line_b sometimes just immediately appear before line_a, i.e., line_b line_a How should your code be changed in order to deal with both cases? > >sed -e ' > /\n/b > /re1/,/re2/!b > /re2/!H;/re1/h;/re2/!d > p;g;s/\n.*//;H;g;D >' yourfile So complicated for me to understand, any hints on your code? Best regards. -- ..: Hongyi Zhao [ hongyi.zhao AT gmail.com ] Free as in Freedom :.
From: Hongyi Zhao on 25 Nov 2009 21:43 On Tue, 24 Nov 2009 17:34:47 +0800, Hongyi Zhao <hongyi.zhao(a)gmail.com> wrote: >Suppose the following should be the final result I want: > >... >here_comes_line_a >... >here_comes_line_b >... Oops, in fact, I want to obtain the following final result: .... .... here_comes_line_a here_comes_line_b .... I.e., line_a should appear just immediately before line_b. Thanks again. -- ..: Hongyi Zhao [ hongyi.zhao AT gmail.com ] Free as in Freedom :.
From: Ed Morton on 25 Nov 2009 22:02 Hongyi Zhao wrote: > On Tue, 24 Nov 2009 17:34:47 +0800, Hongyi Zhao > <hongyi.zhao(a)gmail.com> wrote: > >> Suppose the following should be the final result I want: >> >> ... >> here_comes_line_a >> ... >> here_comes_line_b >> ... > > Oops, in fact, I want to obtain the following final result: > > ... > ... > here_comes_line_a > here_comes_line_b > ... > > I.e., line_a should appear just immediately before line_b. Thanks > again. So, is there actually any swapping involved or do you just want to save line_a and print it before line_b? Ed.
From: Hongyi Zhao on 25 Nov 2009 22:51 On Wed, 25 Nov 2009 21:02:04 -0600, Ed Morton <mortonspam(a)gmail.com> wrote: >So, is there actually any swapping involved or do you just want to save line_a >and print it before line_b? 1- If line_b appears just immediately after line_a, then do nothing. 2- In other cases, move line_b to make sure it just immediately after line_a Best regards. -- ..: Hongyi Zhao [ hongyi.zhao AT gmail.com ] Free as in Freedom :.
From: Ed Morton on 25 Nov 2009 23:41
Hongyi Zhao wrote: > On Wed, 25 Nov 2009 21:02:04 -0600, Ed Morton <mortonspam(a)gmail.com> > wrote: > >> So, is there actually any swapping involved or do you just want to save line_a >> and print it before line_b? > > 1- If line_b appears just immediately after line_a, then do nothing. > > 2- In other cases, move line_b to make sure it just immediately after > line_a > > Best regards. OK, so you don't actually want to swap anything, you want to find "line_b" and move it to earlier in the file, specifically right after "line_a", right? try this: tac file | awk '/line_b/{b=$0 RS; next} /line_a/{printf "%s",b} 1' | tac Ed. |