Replace a string in a file preceeded by another string












3















I have a bunch of config files looking as follows:



reader_0 = newcamd({
name = "Oct 1",
host = "hostname 1",
port = 27020,
user = "UNAME",
pass = "password1",
key = "0102030405060708091011121314",
})

reader_1 = newcamd({
name = "Oct 2",
host = "hostname 2",
port = 27020,
user = "UNAME",
pass = "password2",
key = "0102030405060708091011121314",
})


How can replace a port number 27020 with another one, for example, 22443, in the section 'reader_1' using sed?



Thank you.










share|improve this question




















  • 2





    I think there's a formatting error in your post: You didn't put the four spaces before the closing braces }). This raises the question: Are the two sections from different files or do they belong to one file?

    – Stefan Hamcke
    Jan 10 at 15:14






  • 1





    Are you having reader_3 also?

    – PRY
    Jan 10 at 15:17






  • 1





    What's fixed and what's variable? Is "reader_1 = newcamd({" fixed? Is the existing port always 27020 or can that vary?

    – Jeff Schaller
    Jan 10 at 15:49











  • Will the reader_1 section always have a "port" definition?

    – Jeff Schaller
    Jan 10 at 15:57











  • @JeffSchaller Yes, all reader_* sections have a 'port' parameter. The existing port number is 27020 in all files. All variables are actually constant and same in all files.

    – Viktor Zaionchkovskyi
    Jan 11 at 7:15


















3















I have a bunch of config files looking as follows:



reader_0 = newcamd({
name = "Oct 1",
host = "hostname 1",
port = 27020,
user = "UNAME",
pass = "password1",
key = "0102030405060708091011121314",
})

reader_1 = newcamd({
name = "Oct 2",
host = "hostname 2",
port = 27020,
user = "UNAME",
pass = "password2",
key = "0102030405060708091011121314",
})


How can replace a port number 27020 with another one, for example, 22443, in the section 'reader_1' using sed?



Thank you.










share|improve this question




















  • 2





    I think there's a formatting error in your post: You didn't put the four spaces before the closing braces }). This raises the question: Are the two sections from different files or do they belong to one file?

    – Stefan Hamcke
    Jan 10 at 15:14






  • 1





    Are you having reader_3 also?

    – PRY
    Jan 10 at 15:17






  • 1





    What's fixed and what's variable? Is "reader_1 = newcamd({" fixed? Is the existing port always 27020 or can that vary?

    – Jeff Schaller
    Jan 10 at 15:49











  • Will the reader_1 section always have a "port" definition?

    – Jeff Schaller
    Jan 10 at 15:57











  • @JeffSchaller Yes, all reader_* sections have a 'port' parameter. The existing port number is 27020 in all files. All variables are actually constant and same in all files.

    – Viktor Zaionchkovskyi
    Jan 11 at 7:15
















3












3








3








I have a bunch of config files looking as follows:



reader_0 = newcamd({
name = "Oct 1",
host = "hostname 1",
port = 27020,
user = "UNAME",
pass = "password1",
key = "0102030405060708091011121314",
})

reader_1 = newcamd({
name = "Oct 2",
host = "hostname 2",
port = 27020,
user = "UNAME",
pass = "password2",
key = "0102030405060708091011121314",
})


How can replace a port number 27020 with another one, for example, 22443, in the section 'reader_1' using sed?



Thank you.










share|improve this question
















I have a bunch of config files looking as follows:



reader_0 = newcamd({
name = "Oct 1",
host = "hostname 1",
port = 27020,
user = "UNAME",
pass = "password1",
key = "0102030405060708091011121314",
})

reader_1 = newcamd({
name = "Oct 2",
host = "hostname 2",
port = 27020,
user = "UNAME",
pass = "password2",
key = "0102030405060708091011121314",
})


How can replace a port number 27020 with another one, for example, 22443, in the section 'reader_1' using sed?



Thank you.







sed regular-expression replace






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Jan 10 at 16:51









GAD3R

26.5k1756110




26.5k1756110










asked Jan 10 at 15:01









Viktor ZaionchkovskyiViktor Zaionchkovskyi

183




183








  • 2





    I think there's a formatting error in your post: You didn't put the four spaces before the closing braces }). This raises the question: Are the two sections from different files or do they belong to one file?

    – Stefan Hamcke
    Jan 10 at 15:14






  • 1





    Are you having reader_3 also?

    – PRY
    Jan 10 at 15:17






  • 1





    What's fixed and what's variable? Is "reader_1 = newcamd({" fixed? Is the existing port always 27020 or can that vary?

    – Jeff Schaller
    Jan 10 at 15:49











  • Will the reader_1 section always have a "port" definition?

    – Jeff Schaller
    Jan 10 at 15:57











  • @JeffSchaller Yes, all reader_* sections have a 'port' parameter. The existing port number is 27020 in all files. All variables are actually constant and same in all files.

    – Viktor Zaionchkovskyi
    Jan 11 at 7:15
















  • 2





    I think there's a formatting error in your post: You didn't put the four spaces before the closing braces }). This raises the question: Are the two sections from different files or do they belong to one file?

    – Stefan Hamcke
    Jan 10 at 15:14






  • 1





    Are you having reader_3 also?

    – PRY
    Jan 10 at 15:17






  • 1





    What's fixed and what's variable? Is "reader_1 = newcamd({" fixed? Is the existing port always 27020 or can that vary?

    – Jeff Schaller
    Jan 10 at 15:49











  • Will the reader_1 section always have a "port" definition?

    – Jeff Schaller
    Jan 10 at 15:57











  • @JeffSchaller Yes, all reader_* sections have a 'port' parameter. The existing port number is 27020 in all files. All variables are actually constant and same in all files.

    – Viktor Zaionchkovskyi
    Jan 11 at 7:15










2




2





I think there's a formatting error in your post: You didn't put the four spaces before the closing braces }). This raises the question: Are the two sections from different files or do they belong to one file?

– Stefan Hamcke
Jan 10 at 15:14





I think there's a formatting error in your post: You didn't put the four spaces before the closing braces }). This raises the question: Are the two sections from different files or do they belong to one file?

– Stefan Hamcke
Jan 10 at 15:14




1




1





Are you having reader_3 also?

– PRY
Jan 10 at 15:17





Are you having reader_3 also?

– PRY
Jan 10 at 15:17




1




1





What's fixed and what's variable? Is "reader_1 = newcamd({" fixed? Is the existing port always 27020 or can that vary?

– Jeff Schaller
Jan 10 at 15:49





What's fixed and what's variable? Is "reader_1 = newcamd({" fixed? Is the existing port always 27020 or can that vary?

– Jeff Schaller
Jan 10 at 15:49













Will the reader_1 section always have a "port" definition?

– Jeff Schaller
Jan 10 at 15:57





Will the reader_1 section always have a "port" definition?

– Jeff Schaller
Jan 10 at 15:57













@JeffSchaller Yes, all reader_* sections have a 'port' parameter. The existing port number is 27020 in all files. All variables are actually constant and same in all files.

– Viktor Zaionchkovskyi
Jan 11 at 7:15







@JeffSchaller Yes, all reader_* sections have a 'port' parameter. The existing port number is 27020 in all files. All variables are actually constant and same in all files.

– Viktor Zaionchkovskyi
Jan 11 at 7:15












4 Answers
4






active

oldest

votes


















2














If you have multiple similar lines in the same file you would have to type:



sed -i ':a;N;$!ba; s/27020/22443/2' file



Where /2 would mean that it will replace the second match for 27020. You can test the command with the command sed without the -i parameter in order to see which result gives you.



Otherwise with a simple sed -i 's/27020/22443/g' file it would be valid, as long as you know which file modify.






share|improve this answer



















  • 1





    Thank you. This is what I've been looking for!

    – Viktor Zaionchkovskyi
    Jan 11 at 7:41











  • I used this command for multiple files sed -i -- ':a;N;$!ba; s/27020/22443/2' *

    – Viktor Zaionchkovskyi
    Jan 11 at 7:46



















6














Using sed's predecessor ed:



ed -s input <<< $'/^reader_1 =n/^port =ncnport = 22443,n.nwnq'


This sends ed an ANSI-quoted here-string of commands to edit the file. The commands are, in sequence:





  1. /^reader_1 = -- search for the line beginning with "reader_1 ="


  2. /^port = -- search forwards from there for the line beginning with "port ="


  3. c -- change that line


  4. port = 22443, -- to that text


  5. . -- end the replacement text


  6. w -- write the file to disk


  7. q -- quit ed


You could tighten or loosen the regular expressions to match more or less carefully, according to your actual data.






share|improve this answer

































    3














    I am assuming that reader_0 has host = hostanme 1, reader_1 has host = hostname 2 and so on.



    You can use this command to replace from file:



    sed -i '/host = "hostname 2",/{N;s/port = 27020,/port = 22443,/}' file





    share|improve this answer





















    • 2





      This also assumes that port always follows host. If we assume that the fields and their orders are always the same, then you can also add 2 additional Ns and match from /^reader_1b/ instead of /host = "hostname 2",/.

      – JoL
      Jan 10 at 21:27













    • Yeah, that will be more general.

      – PRY
      Jan 11 at 5:44



















    1














    This might be better done with awk in which you can use a state-machine style technique:



    awk '/^reader_1 = newcamd({/ { section_found = 1} /})/ { section_found = 0 } section_found && /port = 27020,$/ { sub(/27020,$/, "22443,") } { print }' file1 > file2 && mv file2 file1


    Explanation:



    Set a flag when the section start is found:



    /^reader_1 = newcamd({/ {
    section_found = 1
    }


    Clear the flag when the end of a section is found:



    /})/ {
    section_found = 0
    }


    Substitute the new port number when in the right section and on the right line:



    section_found && /port = 27020,$/ {
    sub(/27020,$/, "22443,")
    }


    Print all lines:



    {
    print
    }


    Send output to file2 (a temporary file):



    > file2


    If everything was successful, rename file2 to file1:



    && mv file2 file1


    You can make the regular expressions as loose or tight as you need.



    This type of code is easier to read and maintain than sed or ed code, especially if you format it similarly to the way I have in my explanation.






    share|improve this answer























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      4 Answers
      4






      active

      oldest

      votes








      4 Answers
      4






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes









      2














      If you have multiple similar lines in the same file you would have to type:



      sed -i ':a;N;$!ba; s/27020/22443/2' file



      Where /2 would mean that it will replace the second match for 27020. You can test the command with the command sed without the -i parameter in order to see which result gives you.



      Otherwise with a simple sed -i 's/27020/22443/g' file it would be valid, as long as you know which file modify.






      share|improve this answer



















      • 1





        Thank you. This is what I've been looking for!

        – Viktor Zaionchkovskyi
        Jan 11 at 7:41











      • I used this command for multiple files sed -i -- ':a;N;$!ba; s/27020/22443/2' *

        – Viktor Zaionchkovskyi
        Jan 11 at 7:46
















      2














      If you have multiple similar lines in the same file you would have to type:



      sed -i ':a;N;$!ba; s/27020/22443/2' file



      Where /2 would mean that it will replace the second match for 27020. You can test the command with the command sed without the -i parameter in order to see which result gives you.



      Otherwise with a simple sed -i 's/27020/22443/g' file it would be valid, as long as you know which file modify.






      share|improve this answer



















      • 1





        Thank you. This is what I've been looking for!

        – Viktor Zaionchkovskyi
        Jan 11 at 7:41











      • I used this command for multiple files sed -i -- ':a;N;$!ba; s/27020/22443/2' *

        – Viktor Zaionchkovskyi
        Jan 11 at 7:46














      2












      2








      2







      If you have multiple similar lines in the same file you would have to type:



      sed -i ':a;N;$!ba; s/27020/22443/2' file



      Where /2 would mean that it will replace the second match for 27020. You can test the command with the command sed without the -i parameter in order to see which result gives you.



      Otherwise with a simple sed -i 's/27020/22443/g' file it would be valid, as long as you know which file modify.






      share|improve this answer













      If you have multiple similar lines in the same file you would have to type:



      sed -i ':a;N;$!ba; s/27020/22443/2' file



      Where /2 would mean that it will replace the second match for 27020. You can test the command with the command sed without the -i parameter in order to see which result gives you.



      Otherwise with a simple sed -i 's/27020/22443/g' file it would be valid, as long as you know which file modify.







      share|improve this answer












      share|improve this answer



      share|improve this answer










      answered Jan 10 at 15:13









      DaselDasel

      4497




      4497








      • 1





        Thank you. This is what I've been looking for!

        – Viktor Zaionchkovskyi
        Jan 11 at 7:41











      • I used this command for multiple files sed -i -- ':a;N;$!ba; s/27020/22443/2' *

        – Viktor Zaionchkovskyi
        Jan 11 at 7:46














      • 1





        Thank you. This is what I've been looking for!

        – Viktor Zaionchkovskyi
        Jan 11 at 7:41











      • I used this command for multiple files sed -i -- ':a;N;$!ba; s/27020/22443/2' *

        – Viktor Zaionchkovskyi
        Jan 11 at 7:46








      1




      1





      Thank you. This is what I've been looking for!

      – Viktor Zaionchkovskyi
      Jan 11 at 7:41





      Thank you. This is what I've been looking for!

      – Viktor Zaionchkovskyi
      Jan 11 at 7:41













      I used this command for multiple files sed -i -- ':a;N;$!ba; s/27020/22443/2' *

      – Viktor Zaionchkovskyi
      Jan 11 at 7:46





      I used this command for multiple files sed -i -- ':a;N;$!ba; s/27020/22443/2' *

      – Viktor Zaionchkovskyi
      Jan 11 at 7:46













      6














      Using sed's predecessor ed:



      ed -s input <<< $'/^reader_1 =n/^port =ncnport = 22443,n.nwnq'


      This sends ed an ANSI-quoted here-string of commands to edit the file. The commands are, in sequence:





      1. /^reader_1 = -- search for the line beginning with "reader_1 ="


      2. /^port = -- search forwards from there for the line beginning with "port ="


      3. c -- change that line


      4. port = 22443, -- to that text


      5. . -- end the replacement text


      6. w -- write the file to disk


      7. q -- quit ed


      You could tighten or loosen the regular expressions to match more or less carefully, according to your actual data.






      share|improve this answer






























        6














        Using sed's predecessor ed:



        ed -s input <<< $'/^reader_1 =n/^port =ncnport = 22443,n.nwnq'


        This sends ed an ANSI-quoted here-string of commands to edit the file. The commands are, in sequence:





        1. /^reader_1 = -- search for the line beginning with "reader_1 ="


        2. /^port = -- search forwards from there for the line beginning with "port ="


        3. c -- change that line


        4. port = 22443, -- to that text


        5. . -- end the replacement text


        6. w -- write the file to disk


        7. q -- quit ed


        You could tighten or loosen the regular expressions to match more or less carefully, according to your actual data.






        share|improve this answer




























          6












          6








          6







          Using sed's predecessor ed:



          ed -s input <<< $'/^reader_1 =n/^port =ncnport = 22443,n.nwnq'


          This sends ed an ANSI-quoted here-string of commands to edit the file. The commands are, in sequence:





          1. /^reader_1 = -- search for the line beginning with "reader_1 ="


          2. /^port = -- search forwards from there for the line beginning with "port ="


          3. c -- change that line


          4. port = 22443, -- to that text


          5. . -- end the replacement text


          6. w -- write the file to disk


          7. q -- quit ed


          You could tighten or loosen the regular expressions to match more or less carefully, according to your actual data.






          share|improve this answer















          Using sed's predecessor ed:



          ed -s input <<< $'/^reader_1 =n/^port =ncnport = 22443,n.nwnq'


          This sends ed an ANSI-quoted here-string of commands to edit the file. The commands are, in sequence:





          1. /^reader_1 = -- search for the line beginning with "reader_1 ="


          2. /^port = -- search forwards from there for the line beginning with "port ="


          3. c -- change that line


          4. port = 22443, -- to that text


          5. . -- end the replacement text


          6. w -- write the file to disk


          7. q -- quit ed


          You could tighten or loosen the regular expressions to match more or less carefully, according to your actual data.







          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited Jan 10 at 16:16

























          answered Jan 10 at 16:01









          Jeff SchallerJeff Schaller

          40.9k1056130




          40.9k1056130























              3














              I am assuming that reader_0 has host = hostanme 1, reader_1 has host = hostname 2 and so on.



              You can use this command to replace from file:



              sed -i '/host = "hostname 2",/{N;s/port = 27020,/port = 22443,/}' file





              share|improve this answer





















              • 2





                This also assumes that port always follows host. If we assume that the fields and their orders are always the same, then you can also add 2 additional Ns and match from /^reader_1b/ instead of /host = "hostname 2",/.

                – JoL
                Jan 10 at 21:27













              • Yeah, that will be more general.

                – PRY
                Jan 11 at 5:44
















              3














              I am assuming that reader_0 has host = hostanme 1, reader_1 has host = hostname 2 and so on.



              You can use this command to replace from file:



              sed -i '/host = "hostname 2",/{N;s/port = 27020,/port = 22443,/}' file





              share|improve this answer





















              • 2





                This also assumes that port always follows host. If we assume that the fields and their orders are always the same, then you can also add 2 additional Ns and match from /^reader_1b/ instead of /host = "hostname 2",/.

                – JoL
                Jan 10 at 21:27













              • Yeah, that will be more general.

                – PRY
                Jan 11 at 5:44














              3












              3








              3







              I am assuming that reader_0 has host = hostanme 1, reader_1 has host = hostname 2 and so on.



              You can use this command to replace from file:



              sed -i '/host = "hostname 2",/{N;s/port = 27020,/port = 22443,/}' file





              share|improve this answer















              I am assuming that reader_0 has host = hostanme 1, reader_1 has host = hostname 2 and so on.



              You can use this command to replace from file:



              sed -i '/host = "hostname 2",/{N;s/port = 27020,/port = 22443,/}' file






              share|improve this answer














              share|improve this answer



              share|improve this answer








              edited Jan 11 at 14:53

























              answered Jan 10 at 15:31









              PRYPRY

              1,94131024




              1,94131024








              • 2





                This also assumes that port always follows host. If we assume that the fields and their orders are always the same, then you can also add 2 additional Ns and match from /^reader_1b/ instead of /host = "hostname 2",/.

                – JoL
                Jan 10 at 21:27













              • Yeah, that will be more general.

                – PRY
                Jan 11 at 5:44














              • 2





                This also assumes that port always follows host. If we assume that the fields and their orders are always the same, then you can also add 2 additional Ns and match from /^reader_1b/ instead of /host = "hostname 2",/.

                – JoL
                Jan 10 at 21:27













              • Yeah, that will be more general.

                – PRY
                Jan 11 at 5:44








              2




              2





              This also assumes that port always follows host. If we assume that the fields and their orders are always the same, then you can also add 2 additional Ns and match from /^reader_1b/ instead of /host = "hostname 2",/.

              – JoL
              Jan 10 at 21:27







              This also assumes that port always follows host. If we assume that the fields and their orders are always the same, then you can also add 2 additional Ns and match from /^reader_1b/ instead of /host = "hostname 2",/.

              – JoL
              Jan 10 at 21:27















              Yeah, that will be more general.

              – PRY
              Jan 11 at 5:44





              Yeah, that will be more general.

              – PRY
              Jan 11 at 5:44











              1














              This might be better done with awk in which you can use a state-machine style technique:



              awk '/^reader_1 = newcamd({/ { section_found = 1} /})/ { section_found = 0 } section_found && /port = 27020,$/ { sub(/27020,$/, "22443,") } { print }' file1 > file2 && mv file2 file1


              Explanation:



              Set a flag when the section start is found:



              /^reader_1 = newcamd({/ {
              section_found = 1
              }


              Clear the flag when the end of a section is found:



              /})/ {
              section_found = 0
              }


              Substitute the new port number when in the right section and on the right line:



              section_found && /port = 27020,$/ {
              sub(/27020,$/, "22443,")
              }


              Print all lines:



              {
              print
              }


              Send output to file2 (a temporary file):



              > file2


              If everything was successful, rename file2 to file1:



              && mv file2 file1


              You can make the regular expressions as loose or tight as you need.



              This type of code is easier to read and maintain than sed or ed code, especially if you format it similarly to the way I have in my explanation.






              share|improve this answer




























                1














                This might be better done with awk in which you can use a state-machine style technique:



                awk '/^reader_1 = newcamd({/ { section_found = 1} /})/ { section_found = 0 } section_found && /port = 27020,$/ { sub(/27020,$/, "22443,") } { print }' file1 > file2 && mv file2 file1


                Explanation:



                Set a flag when the section start is found:



                /^reader_1 = newcamd({/ {
                section_found = 1
                }


                Clear the flag when the end of a section is found:



                /})/ {
                section_found = 0
                }


                Substitute the new port number when in the right section and on the right line:



                section_found && /port = 27020,$/ {
                sub(/27020,$/, "22443,")
                }


                Print all lines:



                {
                print
                }


                Send output to file2 (a temporary file):



                > file2


                If everything was successful, rename file2 to file1:



                && mv file2 file1


                You can make the regular expressions as loose or tight as you need.



                This type of code is easier to read and maintain than sed or ed code, especially if you format it similarly to the way I have in my explanation.






                share|improve this answer


























                  1












                  1








                  1







                  This might be better done with awk in which you can use a state-machine style technique:



                  awk '/^reader_1 = newcamd({/ { section_found = 1} /})/ { section_found = 0 } section_found && /port = 27020,$/ { sub(/27020,$/, "22443,") } { print }' file1 > file2 && mv file2 file1


                  Explanation:



                  Set a flag when the section start is found:



                  /^reader_1 = newcamd({/ {
                  section_found = 1
                  }


                  Clear the flag when the end of a section is found:



                  /})/ {
                  section_found = 0
                  }


                  Substitute the new port number when in the right section and on the right line:



                  section_found && /port = 27020,$/ {
                  sub(/27020,$/, "22443,")
                  }


                  Print all lines:



                  {
                  print
                  }


                  Send output to file2 (a temporary file):



                  > file2


                  If everything was successful, rename file2 to file1:



                  && mv file2 file1


                  You can make the regular expressions as loose or tight as you need.



                  This type of code is easier to read and maintain than sed or ed code, especially if you format it similarly to the way I have in my explanation.






                  share|improve this answer













                  This might be better done with awk in which you can use a state-machine style technique:



                  awk '/^reader_1 = newcamd({/ { section_found = 1} /})/ { section_found = 0 } section_found && /port = 27020,$/ { sub(/27020,$/, "22443,") } { print }' file1 > file2 && mv file2 file1


                  Explanation:



                  Set a flag when the section start is found:



                  /^reader_1 = newcamd({/ {
                  section_found = 1
                  }


                  Clear the flag when the end of a section is found:



                  /})/ {
                  section_found = 0
                  }


                  Substitute the new port number when in the right section and on the right line:



                  section_found && /port = 27020,$/ {
                  sub(/27020,$/, "22443,")
                  }


                  Print all lines:



                  {
                  print
                  }


                  Send output to file2 (a temporary file):



                  > file2


                  If everything was successful, rename file2 to file1:



                  && mv file2 file1


                  You can make the regular expressions as loose or tight as you need.



                  This type of code is easier to read and maintain than sed or ed code, especially if you format it similarly to the way I have in my explanation.







                  share|improve this answer












                  share|improve this answer



                  share|improve this answer










                  answered Jan 11 at 0:49









                  Dennis WilliamsonDennis Williamson

                  5,41612332




                  5,41612332






























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