Find – How to Find Files and Use xargs to Move Them

findrenamexargs

I want to find some files and then move them.

I can find the file with:

$ find /tmp/ -ctime -1 -name x*

I tried to move them to my ~/play directory with:

$ find /tmp/ -ctime -1 -name x* | xargs mv ~/play/

but that didn't work. Obviously mv needs two arguments.
Not sure if (or how) to reference the xargs 'current item' in the mv command?

Best Answer

Look at Stephane's answer for the best method, take a look at my answer for reasons not to use the more obvious solutions (and reasons why they are not the most efficient).

You can use the -I option of xargs:

find /tmp/ -ctime -1 -name "x*" | xargs -I '{}' mv '{}' ~/play/

Which works in a similar mechanism to find and {}. I would also quote your -name argument (because a file starting with x in the present directory would be file-globed and passed as an argument to find - which will not give the expected behavior!).

However, as pointed out by manatwork, as detailed in the xargs man page:

   -I replace-str
          Replace occurrences of replace-str in the initial-arguments with
          names read from standard input.  Also, unquoted  blanks  do  not
          terminate  input  items;  instead  the  separator is the newline
          character.  Implies -x and -L 1.

The important thing to note is that -L 1 means that only one line of output from find will be processed at a time. This means that's syntactically the same as:

find /tmp/ -ctime -1 -name "x*" -exec mv '{}' ~/play/

(which executes a single mv operation for each file).

Even using the GNU -0 xargs argument and the find -print0 argument causes exactly the same behavior of -I - this is to clone() a process for each file mv:

find . -name "x*" -print0 | strace xargs -0 -I '{}' mv '{}' /tmp/other

.
.
read(0, "./foobar1/xorgslsala11\0./foobar1"..., 4096) = 870
mmap(NULL, 135168, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =     0x7fbb82fad000
open("/usr/lib/x86_64-linux-gnu/gconv/gconv-modules.cache", O_RDONLY) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=26066, ...}) = 0
mmap(NULL, 26066, PROT_READ, MAP_SHARED, 3, 0) = 0x7fbb82fa6000
close(3)                                = 0
clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD,         child_tidptr=0x7fbb835af9d0) = 661
wait4(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0, NULL) = 661
--- SIGCHLD (Child exited) @ 0 (0) ---
clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD,         child_tidptr=0x7fbb835af9d0) = 662
wait4(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0, NULL) = 662
--- SIGCHLD (Child exited) @ 0 (0) ---
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