在符号链接之后使用find返回符号链接指向的文件，而不是符号链接本身

Question

I use usually use tmutil to control Timemachine instead of the GUI, which has some deficiencies to make it appealable to the masses. I tend to have a lot drives attached to my iMac, at this moment I have 11 with twenty total mounted partitions, but the drives and paritions change as I work on/with them. Sometimes many at a time.

I wrote a one-liner with the goal to report on the exclusion status of all drives in the /Volumes/ directory and an alias to it for simple reuse. alias tmutilvol="find /Volumes/ -maxdepth 1 -exec tmutil isexcluded {} \\;" It works, well mostly. The typical output looks this is,

[Included]    /Volumes
[Excluded]    /Volumes/Backup-Lion
[Excluded]    /Volumes/Backups
[Excluded]    /Volumes/chris
[Excluded]    /Volumes/El Capitan Temp Holding
[Excluded]    /Volumes/Font
[Excluded]    /Volumes/Hades
[Excluded]    /Volumes/iMac Bad
[Excluded]    /Volumes/iMac Clone
[Excluded]    /Volumes/iMac Clone New
[Excluded]    /Volumes/iMac ElCap
[Excluded]    /Volumes/iMac HD
[Excluded]    /Volumes/iMac HD New
[Excluded]    /Volumes/iMac HS Clone
[Excluded]    /Volumes/Macintosh HD Clone 1
[Excluded]    /Volumes/maclaptop
[Excluded]    /Volumes/Old Laptop
[Excluded]    /Volumes/Old-Timemachine-Garnet
[Excluded]    /Volumes/Old-Timemachine-Lion
[Excluded]    /Volumes/TEMPORARY
[Excluded]    /Volumes/Time Machine Mirror

The problem is /Volumes/iMac HD . This is not the actual drive, it is a symlink to it.

drwxr-xr-x   33 chris  staff  1190 Jan 17 12:31 Backup-Lion
drwxrwxr-x   20 chris  staff   748 Nov 11 22:03 Backups
drwxrwxr-x  107 chris  staff  3706 Nov 13 16:26 El Capitan Temp Holding
drwxrwxr-x   82 chris  staff  2856 Jan 19 16:07 Font
drwxr-xr-x  260 chris  staff  8908 Jan 22 11:51 Hades
drwxr-xr-x@  41 chris  staff  1462 Nov 11 22:03 Macintosh HD Clone 1
drwxr-xr-x   24 chris  staff   884 Nov 11 22:03 Old Laptop
drwxr-xr-x    6 chris  staff   272 Jan 17 12:31 Old-Timemachine-Garnet
drwxrwxr-x@  20 chris  staff   748 Jan 19 14:49 Old-Timemachine-Lion
drwxr-xr-x   20 chris  staff   748 Jan 22 11:54 TEMPORARY
drwxr-xr-x   12 chris  staff   476 Jan 23 01:30 Time Machine Mirror
drwx------@   6 chris  staff   272 Jan 16 16:18 chris
drwxrwxrwx   36 chris  staff  1292 Jan 19 00:15 iMac Bad
drwxrwxrwx   29 chris  staff  1054 Nov 13 16:26 iMac Clone
drwxr-xr-x    6 chris  staff   272 Jan 17 16:05 iMac Clone New
drwxr-xr-x   30 chris  staff  1088 Jan 16 17:31 iMac ElCap
lrwxr-xr-x    1 root   wheel     1 Jan 16 20:34 iMac HD -> /
drwxr-xr-x    6 chris  staff   272 Jan 17 16:05 iMac HD New
drwxrwxr-x   26 root   wheel   952 Nov 13 16:26 iMac HS Clone
drwxrwxrwx   40 chris  staff  1428 Jan 19 15:40 maclaptop

The result of tmutil isexcluded is actually for the symlink and not "/"

Kaze:~ chris$ tmutil isexcluded /
[Included]    /

I want to know if there is a way to get find to follow and pass in the destination of the symlink. I read the find man page and about the -L option and thought that would do it and it does not. Some digging on stackexchange https://unix.stackexchange.com/questions/31114/find-usage-with-l explained why it doesn't work. What I have not been able to find is any clue as to how I might do what want and keep a simple one-liner or if I am going to have to write a function for this and deal with symlinks in some convoluted way.

I am hoping that someone with a lot more knowledge of CLI and bash than I might know how to do what I want simply.

Answer 1

Have you tried?

readlink "/Volumes/iMac HD"

one liner for mac:

find /Volumes  -maxdepth 1 -exec bash -c 'N="{}"; L=`readlink "{}"`; tmutil isexcluded "${L:-$N}"' \;

Explanation:

have to use two variables, $L for readlink output, $N for original name.
${L:-$N} basically just output $L if its not empty, else output $N

Note that I have to prefix $L with " /Volumes/ " as MacOS's readlink does not output the absolute path. Linux " readlink -f " solves this issue.