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What does "!{$!..." means in sed ?

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# 1  
Old 03-08-2017
What does "!{$!..." means in sed ?
Hi everyone

i have this command but i have some difficulty to understand it
Code:
 sed -n '/{/!b;:a;/}/!{$!{N;ba;}};{/}/p}' test.trc

the first part it's ok it but for the second pattern with "}" and the ending i have difficulty to understand it.

Can someone explain it to me in detail for each part ?

thanks a lot
# 2  
Old 03-08-2017
Quote:
Originally Posted by ade05fr@yahoo.f
i have this command but i have some difficulty to understand it
Generally: commands in one-liner style do not enhance the readability all too much. If you don't understand it it is a good idea to first write it out, like i have done:


Code:
sed -n '/{/ ! b          # Line rule ("!"=NOTted): if line (not) contains "{", branch
        :a               # target for branching
        /}/ ! {          # line rule (NOTted again): if line (not) contains "}" do
              $ ! {      # line rule (NOTted again): if line is (not) the last line, do
                    N    # append next line to pattern space
                    ba   # branch to target a (see above, line 2)
                  }
              }
        {                # i don't understand this bracket
            /}/p         # line rule: if line contains "}" print it
        }' test.trc

I hope this helps.

bakunin
These 3 Users Gave Thanks to bakunin For This Post:
durden_tyler jim mcnamara RavinderSingh13
# 3  
Old 03-08-2017
Thanks it helps a lot to the comprehension of this command.
This User Gave Thanks to ade05fr@yahoo.f For This Post:
jim mcnamara
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