How to recursively search directories in a minimal shell (no grep, find, etc.)?

Question

I work with an embedded system that works with QNX, which has a truncated shell (KSH).

I want to find everything to run all the executables in the file system that match the following:

*/shle/*-*_test 

The "shle" directory can be displayed up to 4 levels as root. My current approach is to execute the following commands:

 for shle in ./shle ./*/shle ./*/*/shle ./*/*/*/shle do for exe in $shle/*-*_test do echo running: $exe $exe done done 

Is there a cleaner or faster way to do this? Are there any commands other than grep and find that I should try?

Answer 1

If you don't have find , you cannot do much better than what you did: list the levels. If you need to go down to arbitrary levels, you can do this with a recursive function (but look, recursion is complicated when all you have is global variables). Fortunately, with a known maximum depth, this is much easier.

There is little room for improvement: you'd better put double quotation marks around all variable substitutions, if there is a file name containing spaces or special characters. And you do not check if $exe and the executable file exist (it may be a template …/*-*_test if this template does not match anything, or perhaps it may be an unexecutable file).

 for shle in shle */shle */*/shle */*/*/shle; do for exe in "$shle"/*-*_test; do test -x "$exe" && "$exe" done done 

If you do not even have test (if you have ksh, it is built-in, but if it is a stripped-down shell, it may be absent), you can leave with a more complex test to find out if the template has been expanded:

 for shle in shle */shle */*/shle */*/*/shle; do for exe in "$shle"/*-*_test; do case "$exe" in */"*-*_test") :;; *) "$exe";; esac done done 

(I am surprised that you do not have find , I thought that QNX comes with the full POSIX package, but I am not familiar with the QNX ecosystem, it may be a stripped down version of the OS for a small device.)

Answer 2

You can try using the globstar option and specify ** / shle to find directories with one or more levels.

From the ksh man page:

  ∗ Matches any string, including the null string. When used for filename expansion, if the globstar option is on, two adjacent ∗ by itself will match all files and zero or more directories and subdirectories. If followed by a / then only directories and subdirectories will match.