print the first line of those files in current directory which are having last line with a pattern












3














I have multiple log files in a directory and want to print first line of those files which are having pattern vanished on last line.



Could it be done with awk for *.logs having also printed name of the logfile before the first line is printed out?






text-processing awk files







share|improve this question





























    3














    I have multiple log files in a directory and want to print first line of those files which are having pattern vanished on last line.



    Could it be done with awk for *.logs having also printed name of the logfile before the first line is printed out?






    text-processing awk files







    share|improve this question



























      3












      3








      3


      1





      I have multiple log files in a directory and want to print first line of those files which are having pattern vanished on last line.



      Could it be done with awk for *.logs having also printed name of the logfile before the first line is printed out?






      text-processing awk files







      share|improve this question















      I have multiple log files in a directory and want to print first line of those files which are having pattern vanished on last line.



      Could it be done with awk for *.logs having also printed name of the logfile before the first line is printed out?






      text-processing awk files




      text-processing awk files






      share|improve this question















      share|improve this question













      share|improve this question




      share|improve this question








      edited Dec 22 at 17:35









      don_crissti

      49.6k15130159




      49.6k15130159










      asked Dec 22 at 14:44









      Chris

      131111




      131111






















          2 Answers
          2






          active

          oldest

          votes


















          4














          something like this?



          for f in *.logs; do tail -n 1 -- "$f" | grep -q vanished && { printf '%s: ' "$f"; head -n 1 -- "$f"; }; done


          You can also do it with awk but it will be less efficient if the files are big, because you will have to read the whole file, not just the beginning and the end.






          share|improve this answer































            2














            If you want to do this with awk only this could probably get you in the right direction:



            for f in *.log; do awk 'NR==1{ first_line=$0 } END { last_line=$0; print( last_line ~ /varnished/) ? "File: " FILENAME "n" first_line : "" }' "$f"; done


            The for loop is probably not necessarily but this is the most efficient way I could find doing it with awk



            And thanks to the comments below, now we can let gawk do its work as follows:



            gawk 'FNR==1 {first = $0} ENDFILE {if($0 ~ /varnished/) print substr(FILENAME,3) ":", first}' ./*.log


            On recent linux systems, awk is a symlink to gawk. For example, on recent Fedora releases this is the case:



            # ls -l /bin/awk 
            
lrwxrwxrwx. 1 root root 4 Jul 13 07:55 /bin/awk -> gawk





            share|improve this answer



















            • 2




              With a reasonably recent GNU awk you probably could avoid the loop e.g. gawk 'FNR==1 {first = $0} ENDFILE {if($0 ~ /varnished/) print FILENAME ":", first}' *.log
              – steeldriver
              Dec 22 at 17:31






            • 2




              That wouldn't work with files names foo=bar.log for instance. You can work around it by using ./*.log and replace FILENAME with substr(FILENAME, 3).
              – Stéphane Chazelas
              Dec 22 at 18:02











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            2 Answers
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            2 Answers
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            active

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            active

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            active

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            4














            something like this?



            for f in *.logs; do tail -n 1 -- "$f" | grep -q vanished && { printf '%s: ' "$f"; head -n 1 -- "$f"; }; done


            You can also do it with awk but it will be less efficient if the files are big, because you will have to read the whole file, not just the beginning and the end.






            share|improve this answer




























              4














              something like this?



              for f in *.logs; do tail -n 1 -- "$f" | grep -q vanished && { printf '%s: ' "$f"; head -n 1 -- "$f"; }; done


              You can also do it with awk but it will be less efficient if the files are big, because you will have to read the whole file, not just the beginning and the end.






              share|improve this answer


























                4












                4








                4






                something like this?



                for f in *.logs; do tail -n 1 -- "$f" | grep -q vanished && { printf '%s: ' "$f"; head -n 1 -- "$f"; }; done


                You can also do it with awk but it will be less efficient if the files are big, because you will have to read the whole file, not just the beginning and the end.






                share|improve this answer














                something like this?



                for f in *.logs; do tail -n 1 -- "$f" | grep -q vanished && { printf '%s: ' "$f"; head -n 1 -- "$f"; }; done


                You can also do it with awk but it will be less efficient if the files are big, because you will have to read the whole file, not just the beginning and the end.







                share|improve this answer














                share|improve this answer



                share|improve this answer








                edited Dec 22 at 18:00









                Stéphane Chazelas

                299k54563913




                299k54563913










                answered Dec 22 at 15:04









                Uncle Billy

                1935




                1935

























                    2














                    If you want to do this with awk only this could probably get you in the right direction:



                    for f in *.log; do awk 'NR==1{ first_line=$0 } END { last_line=$0; print( last_line ~ /varnished/) ? "File: " FILENAME "n" first_line : "" }' "$f"; done


                    The for loop is probably not necessarily but this is the most efficient way I could find doing it with awk



                    And thanks to the comments below, now we can let gawk do its work as follows:



                    gawk 'FNR==1 {first = $0} ENDFILE {if($0 ~ /varnished/) print substr(FILENAME,3) ":", first}' ./*.log


                    On recent linux systems, awk is a symlink to gawk. For example, on recent Fedora releases this is the case:



                    # ls -l /bin/awk 
                    
lrwxrwxrwx. 1 root root 4 Jul 13 07:55 /bin/awk -> gawk





                    share|improve this answer



















                    • 2




                      With a reasonably recent GNU awk you probably could avoid the loop e.g. gawk 'FNR==1 {first = $0} ENDFILE {if($0 ~ /varnished/) print FILENAME ":", first}' *.log
                      – steeldriver
                      Dec 22 at 17:31






                    • 2




                      That wouldn't work with files names foo=bar.log for instance. You can work around it by using ./*.log and replace FILENAME with substr(FILENAME, 3).
                      – Stéphane Chazelas
                      Dec 22 at 18:02
















                    2














                    If you want to do this with awk only this could probably get you in the right direction:



                    for f in *.log; do awk 'NR==1{ first_line=$0 } END { last_line=$0; print( last_line ~ /varnished/) ? "File: " FILENAME "n" first_line : "" }' "$f"; done


                    The for loop is probably not necessarily but this is the most efficient way I could find doing it with awk



                    And thanks to the comments below, now we can let gawk do its work as follows:



                    gawk 'FNR==1 {first = $0} ENDFILE {if($0 ~ /varnished/) print substr(FILENAME,3) ":", first}' ./*.log


                    On recent linux systems, awk is a symlink to gawk. For example, on recent Fedora releases this is the case:



                    # ls -l /bin/awk 
                    
lrwxrwxrwx. 1 root root 4 Jul 13 07:55 /bin/awk -> gawk





                    share|improve this answer



















                    • 2




                      With a reasonably recent GNU awk you probably could avoid the loop e.g. gawk 'FNR==1 {first = $0} ENDFILE {if($0 ~ /varnished/) print FILENAME ":", first}' *.log
                      – steeldriver
                      Dec 22 at 17:31






                    • 2




                      That wouldn't work with files names foo=bar.log for instance. You can work around it by using ./*.log and replace FILENAME with substr(FILENAME, 3).
                      – Stéphane Chazelas
                      Dec 22 at 18:02














                    2












                    2








                    2






                    If you want to do this with awk only this could probably get you in the right direction:



                    for f in *.log; do awk 'NR==1{ first_line=$0 } END { last_line=$0; print( last_line ~ /varnished/) ? "File: " FILENAME "n" first_line : "" }' "$f"; done


                    The for loop is probably not necessarily but this is the most efficient way I could find doing it with awk



                    And thanks to the comments below, now we can let gawk do its work as follows:



                    gawk 'FNR==1 {first = $0} ENDFILE {if($0 ~ /varnished/) print substr(FILENAME,3) ":", first}' ./*.log


                    On recent linux systems, awk is a symlink to gawk. For example, on recent Fedora releases this is the case:



                    # ls -l /bin/awk 
                    
lrwxrwxrwx. 1 root root 4 Jul 13 07:55 /bin/awk -> gawk





                    share|improve this answer














                    If you want to do this with awk only this could probably get you in the right direction:



                    for f in *.log; do awk 'NR==1{ first_line=$0 } END { last_line=$0; print( last_line ~ /varnished/) ? "File: " FILENAME "n" first_line : "" }' "$f"; done


                    The for loop is probably not necessarily but this is the most efficient way I could find doing it with awk



                    And thanks to the comments below, now we can let gawk do its work as follows:



                    gawk 'FNR==1 {first = $0} ENDFILE {if($0 ~ /varnished/) print substr(FILENAME,3) ":", first}' ./*.log


                    On recent linux systems, awk is a symlink to gawk. For example, on recent Fedora releases this is the case:



                    # ls -l /bin/awk 
                    
lrwxrwxrwx. 1 root root 4 Jul 13 07:55 /bin/awk -> gawk






                    share|improve this answer














                    share|improve this answer



                    share|improve this answer








                    edited 2 days ago

























                    answered Dec 22 at 16:17









                    Valentin Bajrami

                    5,88111627




                    5,88111627








                    • 2




                      With a reasonably recent GNU awk you probably could avoid the loop e.g. gawk 'FNR==1 {first = $0} ENDFILE {if($0 ~ /varnished/) print FILENAME ":", first}' *.log
                      – steeldriver
                      Dec 22 at 17:31






                    • 2




                      That wouldn't work with files names foo=bar.log for instance. You can work around it by using ./*.log and replace FILENAME with substr(FILENAME, 3).
                      – Stéphane Chazelas
                      Dec 22 at 18:02














                    • 2




                      With a reasonably recent GNU awk you probably could avoid the loop e.g. gawk 'FNR==1 {first = $0} ENDFILE {if($0 ~ /varnished/) print FILENAME ":", first}' *.log
                      – steeldriver
                      Dec 22 at 17:31






                    • 2




                      That wouldn't work with files names foo=bar.log for instance. You can work around it by using ./*.log and replace FILENAME with substr(FILENAME, 3).
                      – Stéphane Chazelas
                      Dec 22 at 18:02








                    2




                    2




                    With a reasonably recent GNU awk you probably could avoid the loop e.g. gawk 'FNR==1 {first = $0} ENDFILE {if($0 ~ /varnished/) print FILENAME ":", first}' *.log
                    – steeldriver
                    Dec 22 at 17:31




                    With a reasonably recent GNU awk you probably could avoid the loop e.g. gawk 'FNR==1 {first = $0} ENDFILE {if($0 ~ /varnished/) print FILENAME ":", first}' *.log
                    – steeldriver
                    Dec 22 at 17:31




                    2




                    2




                    That wouldn't work with files names foo=bar.log for instance. You can work around it by using ./*.log and replace FILENAME with substr(FILENAME, 3).
                    – Stéphane Chazelas
                    Dec 22 at 18:02




                    That wouldn't work with files names foo=bar.log for instance. You can work around it by using ./*.log and replace FILENAME with substr(FILENAME, 3).
                    – Stéphane Chazelas
                    Dec 22 at 18:02


















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