How to dump the dmesg AKA Kernel logs to a single .txt file from the kernel boot?












3















I am trying to understand the SATA Host-Device Communication and for that I have put a lot of debug messages in the kernel driver code.
Now messages are in such a huge amount that I am not able to see the initial messages of the device enumeration in the dmesg log. For the same I have modified CONFIG_LOG_BUF_SHIFT(=21) config variable to increase the ring buffer size from where dmesg takes the message but still I am facing the same issue.



So, Is there any method available by which I can log all the dmesg from the kernel boot in to a specific file?



Thanks for the Help in advance.






kernel linux-kernel drivers debugging







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    3















    I am trying to understand the SATA Host-Device Communication and for that I have put a lot of debug messages in the kernel driver code.
    Now messages are in such a huge amount that I am not able to see the initial messages of the device enumeration in the dmesg log. For the same I have modified CONFIG_LOG_BUF_SHIFT(=21) config variable to increase the ring buffer size from where dmesg takes the message but still I am facing the same issue.



    So, Is there any method available by which I can log all the dmesg from the kernel boot in to a specific file?



    Thanks for the Help in advance.






    kernel linux-kernel drivers debugging







    share|improve this question














    bumped to the homepage by Community♦ 3 mins ago


    This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.


















      3












      3








      3








      I am trying to understand the SATA Host-Device Communication and for that I have put a lot of debug messages in the kernel driver code.
      Now messages are in such a huge amount that I am not able to see the initial messages of the device enumeration in the dmesg log. For the same I have modified CONFIG_LOG_BUF_SHIFT(=21) config variable to increase the ring buffer size from where dmesg takes the message but still I am facing the same issue.



      So, Is there any method available by which I can log all the dmesg from the kernel boot in to a specific file?



      Thanks for the Help in advance.






      kernel linux-kernel drivers debugging







      share|improve this question














      I am trying to understand the SATA Host-Device Communication and for that I have put a lot of debug messages in the kernel driver code.
      Now messages are in such a huge amount that I am not able to see the initial messages of the device enumeration in the dmesg log. For the same I have modified CONFIG_LOG_BUF_SHIFT(=21) config variable to increase the ring buffer size from where dmesg takes the message but still I am facing the same issue.



      So, Is there any method available by which I can log all the dmesg from the kernel boot in to a specific file?



      Thanks for the Help in advance.






      kernel linux-kernel drivers debugging




      kernel linux-kernel drivers debugging






      share|improve this question













      share|improve this question











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      asked Feb 11 '16 at 12:17









      HemantHemant

      3318




      3318





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      bumped to the homepage by Community♦ 3 mins ago


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          1 Answer
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          0














          You can use:



          cat /var/log/dmesg > file.txt


          and use:



          head /var/log/dmesg


          if you want to see the first lines of dmesg.



          See too 'man head' for more specifications.
          The '>' symbol redirect the ouput of 'cat' to the 'file.txt'






          share|improve this answer


























          • Thanks for the reply this method I know and tried but it didn't help I want all the messages from start of dmesg. e.g. from "[ 0.000000] Initializing cgroup subsys cpuset"

            – Hemant
            Feb 12 '16 at 4:36













          Your Answer








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          1 Answer
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          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          0














          You can use:



          cat /var/log/dmesg > file.txt


          and use:



          head /var/log/dmesg


          if you want to see the first lines of dmesg.



          See too 'man head' for more specifications.
          The '>' symbol redirect the ouput of 'cat' to the 'file.txt'






          share|improve this answer


























          • Thanks for the reply this method I know and tried but it didn't help I want all the messages from start of dmesg. e.g. from "[ 0.000000] Initializing cgroup subsys cpuset"

            – Hemant
            Feb 12 '16 at 4:36


















          0














          You can use:



          cat /var/log/dmesg > file.txt


          and use:



          head /var/log/dmesg


          if you want to see the first lines of dmesg.



          See too 'man head' for more specifications.
          The '>' symbol redirect the ouput of 'cat' to the 'file.txt'






          share|improve this answer


























          • Thanks for the reply this method I know and tried but it didn't help I want all the messages from start of dmesg. e.g. from "[ 0.000000] Initializing cgroup subsys cpuset"

            – Hemant
            Feb 12 '16 at 4:36
















          0












          0








          0







          You can use:



          cat /var/log/dmesg > file.txt


          and use:



          head /var/log/dmesg


          if you want to see the first lines of dmesg.



          See too 'man head' for more specifications.
          The '>' symbol redirect the ouput of 'cat' to the 'file.txt'






          share|improve this answer















          You can use:



          cat /var/log/dmesg > file.txt


          and use:



          head /var/log/dmesg


          if you want to see the first lines of dmesg.



          See too 'man head' for more specifications.
          The '>' symbol redirect the ouput of 'cat' to the 'file.txt'







          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited Feb 11 '16 at 15:48

























          answered Feb 11 '16 at 15:39









          marcarandmarcarand

          13




          13













          • Thanks for the reply this method I know and tried but it didn't help I want all the messages from start of dmesg. e.g. from "[ 0.000000] Initializing cgroup subsys cpuset"

            – Hemant
            Feb 12 '16 at 4:36





















          • Thanks for the reply this method I know and tried but it didn't help I want all the messages from start of dmesg. e.g. from "[ 0.000000] Initializing cgroup subsys cpuset"

            – Hemant
            Feb 12 '16 at 4:36



















          Thanks for the reply this method I know and tried but it didn't help I want all the messages from start of dmesg. e.g. from "[ 0.000000] Initializing cgroup subsys cpuset"

          – Hemant
          Feb 12 '16 at 4:36







          Thanks for the reply this method I know and tried but it didn't help I want all the messages from start of dmesg. e.g. from "[ 0.000000] Initializing cgroup subsys cpuset"

          – Hemant
          Feb 12 '16 at 4:36




















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