I do not generally use Solaris, but today I need to craft a find command to execute an operation on identified files using the shell. I am finding that the {} characters are not getting substituted and cannot find an alternative.
For example:
bash-3.2# find / -exec sh -c "echo {}" \;
This causes it to print {} for each file instead of the file name.
As written in the man page and in the standard, {} must be in a separate argument.
find / -exec sh -c 'echo $1' dummy '{}' \;
works as expected.
Note that the parameter dummy is needed as the shell assigns the first argument after the command argument for sh -c cmd to become $0 and the next parameter becomes $1.
utility_name or argument string contains the two characters "{}", but not just the two characters "{}", it is implementation-defined whether find replaces those two characters or uses the string without change. It seems GNU find replaces "{}" characters that are combined with other characters, Solaris find does not.
– Andrew Henle
Mar 21 '16 at 20:45
gfind does not behave orthogonal, gfind . -exec echo "aaa {}" \; works as expected, but gfind . -exec echo "aaa {}" + behaves as if gfind . -exec echo "{}" + was called.
– schily
Mar 22 '16 at 17:37
dummy is required by sh, and not by find, since sh -c takes one mandatory argument, the command string here represented by 'echo $1', and optionally other arguments, where the first, dummy in this case, is available in the command as $0, and the following ones, in this case only '{}' (which is not required to be quoted, as far as I can say), as $1, $2, ...
– Enlico
Mar 29 '20 at 09:39
The only standard way to use find -exec … is to pass {} as a separate argument. The behavior when an argument contains {} is not standardized. It seems that you're used to the GNU behavior where {} is substituted in a substring. The find command on Solaris only substitutes {} when an argument consists only of {}.
The GNU behavior is not particularly useful, and sometimes annoying, because substituting a file name inside an argument is brittle. Unless you have known constraints on the file names, there's no way to know where a file name starts and ends. For example, with GNU find, find / -exec sh -c "echo {}" \; does not print the file names in general. It only prints the file names when they don't contain any shell special character. If you run it in a directory containing a file called ;rm -r ~, say goodbye to your files.
The reliable (and portable) way to call a shell from find -exec is to pass the file names as an argument to the shell.
find … -exec sh -c 'echo "$0"' {} \;
In most cases you can pass arguments in batches and iterate over the arguments in the shell. It's somewhat faster. Note that the very first argument after the shell code is $0 which is not includes in "$@".
find … -exec sh -c 'for x; do echo "$x"; done' _ {} +
See also Why does my shell script choke on whitespace or other special characters?
