Find all executable files excluding certain directories

Question

I'm looking to find all executable files that are NOT in my $PATH.

Currently I'm doing this

find / \( -path "/opt" -prune -o -path "/var" -prune -o -path "/bin" -prune -o -path "/sbin" -prune -o -path "/usr" -prune -o -path "/opt" \) -o -type f -executable -exec file {} \;

I feel like there is a better way, I tried using a for loop with IFS=: to separate out the different parts of PATH but couldn't get it to work.

Edit: I should have specified I don't want to use a script for this.

Answer 1

Assuming GNU find and the bash shell (as is used in the question), this is a short script that would accomplish what you're trying to do:

#!/bin/bash

IFS=:
set -f

args=( -false )
for dirpath in $PATH; do
        args+=( -o -path "$dirpath" )
done

find / \( \( "${args[@]}" \) -o \
          \( -type d \( ! -executable -o ! -readable \) \) \) -prune -o \
    -type f -executable -exec file {} +

This first creates the array args, consisting of dynamically constructed arguments to find. It does this by splitting the value of $PATH on colons, the value that we've given to the IFS variable. The splitting is happening when we use $PATH unquoted in the loop header.

Ordinarily, the shell would invoke filename globbing on each of the words generated from the splitting of $PATH, but I'm using set -f to turn off filename globbing, just in case any of the directory paths in $PATH contains globbing characters (these would still be problematic as the -path operand of find would interpret them as patterns).

If my PATH variable contains the string

/usr/bin:/bin:/usr/sbin:/sbin:/usr/X11R6/bin:/usr/local/bin:/usr/local/sbin

then args will be the following list (each line here is a separate element in the array, this is not really a set of strings with newline characters in-between them):

-false
-o
-path
/usr/bin
-o
-path
/bin
-o
-path
/usr/sbin
-o
-path
/sbin
-o
-path
/usr/X11R6/bin
-o
-path
/usr/local/bin
-o
-path
/usr/local/sbin

This list is slotted into the find command invocation, in parentheses. There is no need to repeat -prune for each and every directory, as you could just use it once as I have above.

I've opted for pruning any non-executable or non-readable directory. This ought to get rid of a lot of permission errors for directories that you can't access or list the contents of. Would you want to simplify the find command by removing this bit, use

find / \( "${args[@]}" \) -prune -o \
    -type f -executable -exec file {} +

Also, I'm running file on the found pathnames in batches, rather than once per pathname.

Answer 2

With zsh, you could do:

set -o extendedglob
LC_ALL=C find / -regextype egrep \
  -regex ${(j[|])${(u)path:P}//(#m)[][.\$^*()+{}\\|.]/\\$MATCH} -prune -o \
  -type f -executable -exec file {} +

• $path is a special array tied to the $PATH env var.
• $path:P gets the realpath (absolute, canonical, without symlinks) of each member
• ${(u)array} removes duplicate (here after canonicalisation)
• ${array//(#m)pattern/\\$MATCH} prepends a \ before anything that matches the pattern (here all the egrep regexp operators)
• ${(j[|])array} joins the elements of the array with | to obtain a /dir|/dir\.2|... regexp.