[SOLVED] question on find -exec

timl · 04-27-2016, 06:24 PM

Hi, I want to archive files I update on a sporadic basis but I am struggling with "find -exec"

Quote:

[tim@riverside ~]$ find /mnt/doco/Docs/Resume -mtime -1 -exec cp {} /mnt/doco/Docs/Resume/goldy/ | rm {} \;
find: missing argument to `-exec'
rm: cannot remove '{}': No such file or directory
rm: cannot remove ';': No such file or directory

I also tried

Quote:

[tim@riverside ~]$ find /mnt/doco/Docs/Resume -mtime -1 -exec cp {} /mnt/doco/Docs/Resume/goldy/ | -exec rm {} \;
find: missing argument to `-exec'
bash: -exec: command not found...

However this works

Quote:

[tim@riverside ~]$ find /mnt/doco/Docs/Resume -mtime -1 -exec cp {} /mnt/doco/Docs/Resume/goldy/ \;

Is it correct to include "-exec" two times from the same "find" or should I issue 2 commands? I could probably make life easy and just use "mv" but it would be good to develop a few bash skils.

Cheers

Keith Hedger · 04-27-2016, 06:52 PM

I dont think you can use the pipe to the exec command, so '|-exec' ... wont work as the pipe gets the output of the find command and tries to pipe it to '-exec' which is not a valid command, the -exec arg to find should really only be used with simple commandsvif you need somthing more complex,,mwith pipes to other commands etc I would suggest a wrapper script and -exec that.

rknichols · 04-27-2016, 06:54 PM

Please do not use [QUOTE] tags except to quote from other messages. It makes it hard to quote you in a reply. Use [CODE] ... [/CODE] tags instead.

Quote:

Originally Posted by timl

Code:

find /mnt/doco/Docs/Resume -mtime -1 -exec cp {} /mnt/doco/Docs/Resume/goldy/ | rm {} \;

What do you think that pipe symbol is doing? It causes the shell to split that line into two separate commands, with the find command ending (incompletely) before the pipe symbol and the rest of the line being treated as a separate command removing a nonexistent file named "{}". If you want find to execute two external commands, both constructs have to be complete and end with "\;"

Code:

find /mnt/doco/Docs/Resume -mtime -1 -exec cp {} /mnt/doco/Docs/Resume/goldy/ \; -exec rm {} \;

The rm command will be executed only if the cp succeeds. That could also be done by telling find itself to delete the file:

Code:

find /mnt/doco/Docs/Resume -mtime -1 -exec cp {} /mnt/doco/Docs/Resume/goldy/ \; -delete

(Either one is a near-equivalent to a mv command.)

If you really meant that "|" to be a pipe, why would you be piping the stdout of cp (which does not write anything to its stdout) to the stdin of rm (which does not read from its stdin)?

sundialsvcs · 04-27-2016, 07:24 PM

Ordinarily, I let find produce a list of filenames, which I then pipe into the xargs command . . .

timl · 04-27-2016, 08:25 PM

Thanks all, I decided to RTFM now I understand the command a bit more and it seems "-depth" is a useful switch also (in liaison with -delete").

"xargs"!! There is something else to research. Not really sure how that works but now may be the time to try. Thanks for the heads up

Cheers

rknichols · 04-27-2016, 08:31 PM

Quote:

Originally Posted by timl

Thanks all, I decided to RTFM now I understand the command a bit more and it seems "-depth" is a useful switch also (in liaison with -delete").

The authors of find thought that combination was important too, so much so that "-delete" implies "-depth".

sundialsvcs · 04-28-2016, 06:52 AM

xargs stands for "execute with arguments."

This command reads lines from STDIN, assembles these into commands (as specified on the xargs command-line), and spawns shells to execute them. Some versions can execute multiple shells in parallel.

grep -rilw foobar /here | xargs -I{} mv {} /there

This example first uses the "grep" command to locate all files in "/here" which contain the word "foobar." It pipes that output to xargs, to execute a "mv" command to move the files "/there." "{}" is specified (using the "-I" option ...) as a placeholder where the name (read from STDIN) is inserted into the command.

So, if it reads the string "tomcat," it will execute mv tomcat /there ... and so on.