I’m trying to make symbolic links in my Dropbox so that I don’t have duplicate files all over my computer (file space is limited). I’ve come across some confusing behavior in ln -s vs. cp -s. Basically, ln -s seems to make a link to the original folder, but then copies all the files within the folder to a new location. cp -sr recursively makes links to all files within the folder (which is the desired behavior).
For example:
nate@auerilas ~ $ mkdir ~/Desktop/test_lnnate@auerilas ~ $ mkdir ~/Desktop/test_cpnate@auerilas ~ $ cp -sr ~/Documents/GIS_Files/WorldClim2/Monthly/Prec/ ~/Desktop/test_cpnate@auerilas ~ $ ln -s ~/Documents/GIS_Files/WorldClim2/Monthly/Prec/ ~/Desktop/test_lnnate@auerilas ~ $ cd ~/Desktop/test_cp/Precnate@auerilas ~/Desktop/test_cp/Prec $ ls -lstotal 524 lrwxrwxrwx 1 nate nate 65 Apr 27 11:40 readme.txt -> /home/nate/Documents/GIS_Files/WorldClim2/Monthly/Prec/readme.txt4 lrwxrwxrwx 1 nate nate 76 Apr 27 11:40 wc2.0_30s_prec_01.tif -> /home/nate/Documents/GIS_Files/WorldClim2/Monthly/Prec/wc2.0_30s_prec_01.tif4 lrwxrwxrwx 1 nate nate 76 Apr 27 11:40 wc2.0_30s_prec_02.tif -> /home/nate/Documents/GIS_Files/WorldClim2/Monthly/Prec/wc2.0_30s_prec_02.tif4 lrwxrwxrwx 1 nate nate 76 Apr 27 11:40 wc2.0_30s_prec_03.tif -> /home/nate/Documents/GIS_Files/WorldClim2/Monthly/Prec/wc2.0_30s_prec_03.tif4 lrwxrwxrwx 1 nate nate 76 Apr 27 11:40 wc2.0_30s_prec_04.tif -> /home/nate/Documents/GIS_Files/WorldClim2/Monthly/Prec/wc2.0_30s_prec_04.tif4 lrwxrwxrwx 1 nate nate 76 Apr 27 11:40 wc2.0_30s_prec_05.tif -> /home/nate/Documents/GIS_Files/WorldClim2/Monthly/Prec/wc2.0_30s_prec_05.tif4 lrwxrwxrwx 1 nate nate 76 Apr 27 11:40 wc2.0_30s_prec_06.tif -> /home/nate/Documents/GIS_Files/WorldClim2/Monthly/Prec/wc2.0_30s_prec_06.tif4 lrwxrwxrwx 1 nate nate 76 Apr 27 11:40 wc2.0_30s_prec_07.tif -> /home/nate/Documents/GIS_Files/WorldClim2/Monthly/Prec/wc2.0_30s_prec_07.tif4 lrwxrwxrwx 1 nate nate 76 Apr 27 11:40 wc2.0_30s_prec_08.tif -> /home/nate/Documents/GIS_Files/WorldClim2/Monthly/Prec/wc2.0_30s_prec_08.tif4 lrwxrwxrwx 1 nate nate 76 Apr 27 11:40 wc2.0_30s_prec_09.tif -> /home/nate/Documents/GIS_Files/WorldClim2/Monthly/Prec/wc2.0_30s_prec_09.tif4 lrwxrwxrwx 1 nate nate 76 Apr 27 11:40 wc2.0_30s_prec_10.tif -> /home/nate/Documents/GIS_Files/WorldClim2/Monthly/Prec/wc2.0_30s_prec_10.tif4 lrwxrwxrwx 1 nate nate 76 Apr 27 11:40 wc2.0_30s_prec_11.tif -> /home/nate/Documents/GIS_Files/WorldClim2/Monthly/Prec/wc2.0_30s_prec_11.tif4 lrwxrwxrwx 1 nate nate 76 Apr 27 11:40 wc2.0_30s_prec_12.tif -> /home/nate/Documents/GIS_Files/WorldClim2/Monthly/Prec/wc2.0_30s_prec_12.tifnate@auerilas ~ $ cd ~/Desktop/test_ln/Precnate@auerilas ~/Desktop/test_ln/Prec $ ls -lstotal 1030608 8 -rw-rw-r-- 1 nate nate 256 Jul 4 2016 readme.txt74828 -rw-rw-r-- 1 nate nate 76618603 Jun 30 2016 wc2.0_30s_prec_01.tif76620 -rw-rw-r-- 1 nate nate 78453928 Jun 30 2016 wc2.0_30s_prec_02.tif86664 -rw-rw-r-- 1 nate nate 88738160 Jun 30 2016 wc2.0_30s_prec_03.tif89424 -rw-rw-r-- 1 nate nate 91564709 Jun 30 2016 wc2.0_30s_prec_04.tif88272 -rw-rw-r-- 1 nate nate 90386408 Jun 30 2016 wc2.0_30s_prec_05.tif90364 -rw-rw-r-- 1 nate nate 92524861 Jun 30 2016 wc2.0_30s_prec_06.tif92252 -rw-rw-r-- 1 nate nate 94459125 Jun 30 2016 wc2.0_30s_prec_07.tif94700 -rw-rw-r-- 1 nate nate 96964870 Jun 30 2016 wc2.0_30s_prec_08.tif88708 -rw-rw-r-- 1 nate nate 90829431 Jun 30 2016 wc2.0_30s_prec_09.tif92756 -rw-rw-r-- 1 nate nate 94977702 Jun 30 2016 wc2.0_30s_prec_10.tif79808 -rw-rw-r-- 1 nate nate 81716504 Jun 30 2016 wc2.0_30s_prec_11.tif76204 -rw-rw-r-- 1 nate nate 78025342 Jun 30 2016 wc2.0_30s_prec_12.tifNote the difference in file sizes between the two methods, and the lack of a link for the files made by ln -s. If I go into my file browser and right click to look at the properties, I also see something different.
ln -s
Type ImageSize 76.6 MBLocation /home/nate/Desktop/test_ln/Preccp -sr
Type Link to ImageLink target /home/nate/Documents/GIS_File..nthly/Prec/wc2.0Size 76.6 MBLocation /home/nate/Desktop/test_cp/PrecSo cp -sr seems to be actually linking each file in a directory, whereas ln -s seems to link the top folder only and copying the files within the folder, thus duplicating files.
Is that correct?
The problem is that if I use cp -sr, only the files themselves are linked, not the top folder. So if I add or delete a file on my harddrive, the change isn’t then copied to Dropbox
Running Linux Mint 18.3
Advertisement
Answer
You’re correct. Here’s info cp explicitly saying that it only links non-directories:
JavaScript‘-s’‘--symbolic-link’Make symbolic links instead of copies of non-directories.