Copy files in Linux, avoid the copy if files do exist in destination











up vote
22
down vote

favorite
8












I need to copy a /home/user folder from one hard disk to another one. It has 100,000 files and around 10G size.



I use




cp -r /origin /destination




sometimes I get some errors due to broken links, permissions and so on. So I fix the error, and need to start again the copy.



I wonder how could I tell the command "cp", once it tries to copy again, not to copy files again if they exist in the destination folder.










share|improve this question















migrated from stackoverflow.com Mar 11 '10 at 16:51


This question came from our site for professional and enthusiast programmers.











  • 1




    Don't us cp. Use rsync instead.
    – William Pursell
    Mar 11 '10 at 16:08

















up vote
22
down vote

favorite
8












I need to copy a /home/user folder from one hard disk to another one. It has 100,000 files and around 10G size.



I use




cp -r /origin /destination




sometimes I get some errors due to broken links, permissions and so on. So I fix the error, and need to start again the copy.



I wonder how could I tell the command "cp", once it tries to copy again, not to copy files again if they exist in the destination folder.










share|improve this question















migrated from stackoverflow.com Mar 11 '10 at 16:51


This question came from our site for professional and enthusiast programmers.











  • 1




    Don't us cp. Use rsync instead.
    – William Pursell
    Mar 11 '10 at 16:08















up vote
22
down vote

favorite
8









up vote
22
down vote

favorite
8






8





I need to copy a /home/user folder from one hard disk to another one. It has 100,000 files and around 10G size.



I use




cp -r /origin /destination




sometimes I get some errors due to broken links, permissions and so on. So I fix the error, and need to start again the copy.



I wonder how could I tell the command "cp", once it tries to copy again, not to copy files again if they exist in the destination folder.










share|improve this question















I need to copy a /home/user folder from one hard disk to another one. It has 100,000 files and around 10G size.



I use




cp -r /origin /destination




sometimes I get some errors due to broken links, permissions and so on. So I fix the error, and need to start again the copy.



I wonder how could I tell the command "cp", once it tries to copy again, not to copy files again if they exist in the destination folder.







linux bash






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Feb 11 '11 at 16:31









studiohack

11.3k1880113




11.3k1880113










asked Mar 11 '10 at 15:59









flow

1,986133964




1,986133964




migrated from stackoverflow.com Mar 11 '10 at 16:51


This question came from our site for professional and enthusiast programmers.






migrated from stackoverflow.com Mar 11 '10 at 16:51


This question came from our site for professional and enthusiast programmers.










  • 1




    Don't us cp. Use rsync instead.
    – William Pursell
    Mar 11 '10 at 16:08
















  • 1




    Don't us cp. Use rsync instead.
    – William Pursell
    Mar 11 '10 at 16:08










1




1




Don't us cp. Use rsync instead.
– William Pursell
Mar 11 '10 at 16:08






Don't us cp. Use rsync instead.
– William Pursell
Mar 11 '10 at 16:08












7 Answers
7






active

oldest

votes

















up vote
17
down vote



accepted










cp -R -u -p /source /destination



The -u (or --update) flag does just this:



From the man page for cp:




-u, --update



copy only when the SOURCE file is newer than the destination file or when the destination file is missing







share|improve this answer



















  • 4




    To literally only copy files that don't exist and not update existing ones, yes n | cp -i /source/* /destination 2>/dev/null
    – sventechie
    Nov 21 '13 at 20:14








  • 3




    -u, --update copy only when the SOURCE file is newer than the destination file or when the destination file is missing -u, --update copy only when the SOURCE file is newer than the destination file or when the destination file is missing -p same as --preserve=mode,ownership,timestamps --preserve[=ATTR_LIST] preserve the specified attributes (default: mode,ownership,time‐ stamps), if possible additional attributes: context, links, xattr, all
    – Covich
    Feb 16 '16 at 15:29




















up vote
20
down vote













Just use cp -n <source> <dest>.



From man page:




-n, --no-clobber



do NOT overwrite an existing file (overrides a previous -i option)







share|improve this answer



















  • 4




    This is the only true answer to the question.
    – sebix
    Mar 21 '17 at 18:19


















up vote
16
down vote













rsync -aq /src /dest



Apart from only copying newer files, it will even only copy the newer parts of files if the file has changed. It's intended for copying over network links where you want to minimise the amount of data - but it also works great locally.






share|improve this answer























  • I can't add `` formatting to your post because it's only two characters. How would you feel about editing this and adding `` characters around your command?
    – culix
    Apr 24 '16 at 18:02


















up vote
4
down vote













Look up the "-u" option for the cp command.






share|improve this answer

















  • 2




    Disagree that using -u is a good idea. -u copies only when source is newer or destination is missing. Original poster's issue was caused by file copy breaking for whatever reason. OP would therefore have half-written file that wasn't updated when re-running the copy. That file might be important to someone! rsync solves this problem.
    – hazymat
    Dec 21 '13 at 21:47


















up vote
1
down vote













You should be copying as root to maintain permissions/ownership



# cp -au


Also look at rsync






share|improve this answer




























    up vote
    1
    down vote













    All above answers are correct but if you are doing this recursively then



    you should do:



     cp -rn SOURCE_PATH DESTINATION_PATH





    share|improve this answer




























      up vote
      0
      down vote













      POSIX solution



      Other answers use -u or -n options of cp. Neither of these is required by POSIX; nor is rsync from yet another answer; nor is yes used in one of the comments.



      Still we can reproduce yes n with a while loop. This leads to the following POSIX solution:



      while true; do echo n; done | cp -Ri /origin /destination 2>/dev/null





      share|improve this answer





















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        7 Answers
        7






        active

        oldest

        votes








        7 Answers
        7






        active

        oldest

        votes









        active

        oldest

        votes






        active

        oldest

        votes








        up vote
        17
        down vote



        accepted










        cp -R -u -p /source /destination



        The -u (or --update) flag does just this:



        From the man page for cp:




        -u, --update



        copy only when the SOURCE file is newer than the destination file or when the destination file is missing







        share|improve this answer



















        • 4




          To literally only copy files that don't exist and not update existing ones, yes n | cp -i /source/* /destination 2>/dev/null
          – sventechie
          Nov 21 '13 at 20:14








        • 3




          -u, --update copy only when the SOURCE file is newer than the destination file or when the destination file is missing -u, --update copy only when the SOURCE file is newer than the destination file or when the destination file is missing -p same as --preserve=mode,ownership,timestamps --preserve[=ATTR_LIST] preserve the specified attributes (default: mode,ownership,time‐ stamps), if possible additional attributes: context, links, xattr, all
          – Covich
          Feb 16 '16 at 15:29

















        up vote
        17
        down vote



        accepted










        cp -R -u -p /source /destination



        The -u (or --update) flag does just this:



        From the man page for cp:




        -u, --update



        copy only when the SOURCE file is newer than the destination file or when the destination file is missing







        share|improve this answer



















        • 4




          To literally only copy files that don't exist and not update existing ones, yes n | cp -i /source/* /destination 2>/dev/null
          – sventechie
          Nov 21 '13 at 20:14








        • 3




          -u, --update copy only when the SOURCE file is newer than the destination file or when the destination file is missing -u, --update copy only when the SOURCE file is newer than the destination file or when the destination file is missing -p same as --preserve=mode,ownership,timestamps --preserve[=ATTR_LIST] preserve the specified attributes (default: mode,ownership,time‐ stamps), if possible additional attributes: context, links, xattr, all
          – Covich
          Feb 16 '16 at 15:29















        up vote
        17
        down vote



        accepted







        up vote
        17
        down vote



        accepted






        cp -R -u -p /source /destination



        The -u (or --update) flag does just this:



        From the man page for cp:




        -u, --update



        copy only when the SOURCE file is newer than the destination file or when the destination file is missing







        share|improve this answer














        cp -R -u -p /source /destination



        The -u (or --update) flag does just this:



        From the man page for cp:




        -u, --update



        copy only when the SOURCE file is newer than the destination file or when the destination file is missing








        share|improve this answer














        share|improve this answer



        share|improve this answer








        edited Nov 23 at 0:39









        ifconfig

        1731215




        1731215










        answered Mar 11 '10 at 16:02









        user31894

        2,105129




        2,105129








        • 4




          To literally only copy files that don't exist and not update existing ones, yes n | cp -i /source/* /destination 2>/dev/null
          – sventechie
          Nov 21 '13 at 20:14








        • 3




          -u, --update copy only when the SOURCE file is newer than the destination file or when the destination file is missing -u, --update copy only when the SOURCE file is newer than the destination file or when the destination file is missing -p same as --preserve=mode,ownership,timestamps --preserve[=ATTR_LIST] preserve the specified attributes (default: mode,ownership,time‐ stamps), if possible additional attributes: context, links, xattr, all
          – Covich
          Feb 16 '16 at 15:29
















        • 4




          To literally only copy files that don't exist and not update existing ones, yes n | cp -i /source/* /destination 2>/dev/null
          – sventechie
          Nov 21 '13 at 20:14








        • 3




          -u, --update copy only when the SOURCE file is newer than the destination file or when the destination file is missing -u, --update copy only when the SOURCE file is newer than the destination file or when the destination file is missing -p same as --preserve=mode,ownership,timestamps --preserve[=ATTR_LIST] preserve the specified attributes (default: mode,ownership,time‐ stamps), if possible additional attributes: context, links, xattr, all
          – Covich
          Feb 16 '16 at 15:29










        4




        4




        To literally only copy files that don't exist and not update existing ones, yes n | cp -i /source/* /destination 2>/dev/null
        – sventechie
        Nov 21 '13 at 20:14






        To literally only copy files that don't exist and not update existing ones, yes n | cp -i /source/* /destination 2>/dev/null
        – sventechie
        Nov 21 '13 at 20:14






        3




        3




        -u, --update copy only when the SOURCE file is newer than the destination file or when the destination file is missing -u, --update copy only when the SOURCE file is newer than the destination file or when the destination file is missing -p same as --preserve=mode,ownership,timestamps --preserve[=ATTR_LIST] preserve the specified attributes (default: mode,ownership,time‐ stamps), if possible additional attributes: context, links, xattr, all
        – Covich
        Feb 16 '16 at 15:29






        -u, --update copy only when the SOURCE file is newer than the destination file or when the destination file is missing -u, --update copy only when the SOURCE file is newer than the destination file or when the destination file is missing -p same as --preserve=mode,ownership,timestamps --preserve[=ATTR_LIST] preserve the specified attributes (default: mode,ownership,time‐ stamps), if possible additional attributes: context, links, xattr, all
        – Covich
        Feb 16 '16 at 15:29














        up vote
        20
        down vote













        Just use cp -n <source> <dest>.



        From man page:




        -n, --no-clobber



        do NOT overwrite an existing file (overrides a previous -i option)







        share|improve this answer



















        • 4




          This is the only true answer to the question.
          – sebix
          Mar 21 '17 at 18:19















        up vote
        20
        down vote













        Just use cp -n <source> <dest>.



        From man page:




        -n, --no-clobber



        do NOT overwrite an existing file (overrides a previous -i option)







        share|improve this answer



















        • 4




          This is the only true answer to the question.
          – sebix
          Mar 21 '17 at 18:19













        up vote
        20
        down vote










        up vote
        20
        down vote









        Just use cp -n <source> <dest>.



        From man page:




        -n, --no-clobber



        do NOT overwrite an existing file (overrides a previous -i option)







        share|improve this answer














        Just use cp -n <source> <dest>.



        From man page:




        -n, --no-clobber



        do NOT overwrite an existing file (overrides a previous -i option)








        share|improve this answer














        share|improve this answer



        share|improve this answer








        edited Jan 25 '17 at 15:59









        Adalee

        312410




        312410










        answered Jan 25 '17 at 13:45









        Balmipour

        32926




        32926








        • 4




          This is the only true answer to the question.
          – sebix
          Mar 21 '17 at 18:19














        • 4




          This is the only true answer to the question.
          – sebix
          Mar 21 '17 at 18:19








        4




        4




        This is the only true answer to the question.
        – sebix
        Mar 21 '17 at 18:19




        This is the only true answer to the question.
        – sebix
        Mar 21 '17 at 18:19










        up vote
        16
        down vote













        rsync -aq /src /dest



        Apart from only copying newer files, it will even only copy the newer parts of files if the file has changed. It's intended for copying over network links where you want to minimise the amount of data - but it also works great locally.






        share|improve this answer























        • I can't add `` formatting to your post because it's only two characters. How would you feel about editing this and adding `` characters around your command?
          – culix
          Apr 24 '16 at 18:02















        up vote
        16
        down vote













        rsync -aq /src /dest



        Apart from only copying newer files, it will even only copy the newer parts of files if the file has changed. It's intended for copying over network links where you want to minimise the amount of data - but it also works great locally.






        share|improve this answer























        • I can't add `` formatting to your post because it's only two characters. How would you feel about editing this and adding `` characters around your command?
          – culix
          Apr 24 '16 at 18:02













        up vote
        16
        down vote










        up vote
        16
        down vote









        rsync -aq /src /dest



        Apart from only copying newer files, it will even only copy the newer parts of files if the file has changed. It's intended for copying over network links where you want to minimise the amount of data - but it also works great locally.






        share|improve this answer














        rsync -aq /src /dest



        Apart from only copying newer files, it will even only copy the newer parts of files if the file has changed. It's intended for copying over network links where you want to minimise the amount of data - but it also works great locally.







        share|improve this answer














        share|improve this answer



        share|improve this answer








        edited Apr 24 '16 at 21:17

























        answered Mar 11 '10 at 16:12









        Martin Beckett

        4,75311925




        4,75311925












        • I can't add `` formatting to your post because it's only two characters. How would you feel about editing this and adding `` characters around your command?
          – culix
          Apr 24 '16 at 18:02


















        • I can't add `` formatting to your post because it's only two characters. How would you feel about editing this and adding `` characters around your command?
          – culix
          Apr 24 '16 at 18:02
















        I can't add `` formatting to your post because it's only two characters. How would you feel about editing this and adding `` characters around your command?
        – culix
        Apr 24 '16 at 18:02




        I can't add `` formatting to your post because it's only two characters. How would you feel about editing this and adding `` characters around your command?
        – culix
        Apr 24 '16 at 18:02










        up vote
        4
        down vote













        Look up the "-u" option for the cp command.






        share|improve this answer

















        • 2




          Disagree that using -u is a good idea. -u copies only when source is newer or destination is missing. Original poster's issue was caused by file copy breaking for whatever reason. OP would therefore have half-written file that wasn't updated when re-running the copy. That file might be important to someone! rsync solves this problem.
          – hazymat
          Dec 21 '13 at 21:47















        up vote
        4
        down vote













        Look up the "-u" option for the cp command.






        share|improve this answer

















        • 2




          Disagree that using -u is a good idea. -u copies only when source is newer or destination is missing. Original poster's issue was caused by file copy breaking for whatever reason. OP would therefore have half-written file that wasn't updated when re-running the copy. That file might be important to someone! rsync solves this problem.
          – hazymat
          Dec 21 '13 at 21:47













        up vote
        4
        down vote










        up vote
        4
        down vote









        Look up the "-u" option for the cp command.






        share|improve this answer












        Look up the "-u" option for the cp command.







        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered Mar 11 '10 at 16:01









        Pointy

        5931520




        5931520








        • 2




          Disagree that using -u is a good idea. -u copies only when source is newer or destination is missing. Original poster's issue was caused by file copy breaking for whatever reason. OP would therefore have half-written file that wasn't updated when re-running the copy. That file might be important to someone! rsync solves this problem.
          – hazymat
          Dec 21 '13 at 21:47














        • 2




          Disagree that using -u is a good idea. -u copies only when source is newer or destination is missing. Original poster's issue was caused by file copy breaking for whatever reason. OP would therefore have half-written file that wasn't updated when re-running the copy. That file might be important to someone! rsync solves this problem.
          – hazymat
          Dec 21 '13 at 21:47








        2




        2




        Disagree that using -u is a good idea. -u copies only when source is newer or destination is missing. Original poster's issue was caused by file copy breaking for whatever reason. OP would therefore have half-written file that wasn't updated when re-running the copy. That file might be important to someone! rsync solves this problem.
        – hazymat
        Dec 21 '13 at 21:47




        Disagree that using -u is a good idea. -u copies only when source is newer or destination is missing. Original poster's issue was caused by file copy breaking for whatever reason. OP would therefore have half-written file that wasn't updated when re-running the copy. That file might be important to someone! rsync solves this problem.
        – hazymat
        Dec 21 '13 at 21:47










        up vote
        1
        down vote













        You should be copying as root to maintain permissions/ownership



        # cp -au


        Also look at rsync






        share|improve this answer

























          up vote
          1
          down vote













          You should be copying as root to maintain permissions/ownership



          # cp -au


          Also look at rsync






          share|improve this answer























            up vote
            1
            down vote










            up vote
            1
            down vote









            You should be copying as root to maintain permissions/ownership



            # cp -au


            Also look at rsync






            share|improve this answer












            You should be copying as root to maintain permissions/ownership



            # cp -au


            Also look at rsync







            share|improve this answer












            share|improve this answer



            share|improve this answer










            answered Mar 11 '10 at 16:09









            pixelbeat

            85066




            85066






















                up vote
                1
                down vote













                All above answers are correct but if you are doing this recursively then



                you should do:



                 cp -rn SOURCE_PATH DESTINATION_PATH





                share|improve this answer

























                  up vote
                  1
                  down vote













                  All above answers are correct but if you are doing this recursively then



                  you should do:



                   cp -rn SOURCE_PATH DESTINATION_PATH





                  share|improve this answer























                    up vote
                    1
                    down vote










                    up vote
                    1
                    down vote









                    All above answers are correct but if you are doing this recursively then



                    you should do:



                     cp -rn SOURCE_PATH DESTINATION_PATH





                    share|improve this answer












                    All above answers are correct but if you are doing this recursively then



                    you should do:



                     cp -rn SOURCE_PATH DESTINATION_PATH






                    share|improve this answer












                    share|improve this answer



                    share|improve this answer










                    answered Jul 8 at 4:58









                    nanoseconds

                    1236




                    1236






















                        up vote
                        0
                        down vote













                        POSIX solution



                        Other answers use -u or -n options of cp. Neither of these is required by POSIX; nor is rsync from yet another answer; nor is yes used in one of the comments.



                        Still we can reproduce yes n with a while loop. This leads to the following POSIX solution:



                        while true; do echo n; done | cp -Ri /origin /destination 2>/dev/null





                        share|improve this answer

























                          up vote
                          0
                          down vote













                          POSIX solution



                          Other answers use -u or -n options of cp. Neither of these is required by POSIX; nor is rsync from yet another answer; nor is yes used in one of the comments.



                          Still we can reproduce yes n with a while loop. This leads to the following POSIX solution:



                          while true; do echo n; done | cp -Ri /origin /destination 2>/dev/null





                          share|improve this answer























                            up vote
                            0
                            down vote










                            up vote
                            0
                            down vote









                            POSIX solution



                            Other answers use -u or -n options of cp. Neither of these is required by POSIX; nor is rsync from yet another answer; nor is yes used in one of the comments.



                            Still we can reproduce yes n with a while loop. This leads to the following POSIX solution:



                            while true; do echo n; done | cp -Ri /origin /destination 2>/dev/null





                            share|improve this answer












                            POSIX solution



                            Other answers use -u or -n options of cp. Neither of these is required by POSIX; nor is rsync from yet another answer; nor is yes used in one of the comments.



                            Still we can reproduce yes n with a while loop. This leads to the following POSIX solution:



                            while true; do echo n; done | cp -Ri /origin /destination 2>/dev/null






                            share|improve this answer












                            share|improve this answer



                            share|improve this answer










                            answered Nov 23 at 6:33









                            Kamil Maciorowski

                            22.8k155072




                            22.8k155072






























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