How to execute shell builtins using incus exec

1

While trying to interact using the API I’ve just discovered that incus exec doesn’t run shell builtins. Trying to run the same command manually shows it can’t be execd outside the instance

incus exec trixie -- "! (test -e /root/yofile || test -L /root/yofile ) || ( stat -c 'user=%U group=%G mode=%A atime=%X mtime=%Y ctime=%Z size=%s %N' /root/yofile 2> /dev/null || stat -f 'user=%Su group=%Sg mode=%Sp atime=%a mtime=%m ctime=%c size=%z %N%SY' /root/yofile )"
Error: Command not found

but these same commands do work when run directly in an instance:

root@trixie:/# ! (test -e /root/yofile || test -L /root/yofile ) || ( stat -c 'user=%U group=%G mode=%A atime=%X mtime=%Y ctime=%Z size=%s %N' /root/yofile 2> /dev/null || stat -f 'user=%Su group=%Sg mode=%Sp atime=%a mtime=%m ctime=%c size=%z %N%SY' /root/yofile )
user=root group=root mode=-rw-r--r-- atime=1754357120 mtime=1754357120 ctime=1754357120 size=0 '/root/yofile'

Is there a flag/setting I’ve missed which instructs incus to also attempt shell builtins or do I need to wrap the tests up in some extra ‘shell -c’ magic to try and work around this? eg:

incus exec trixie -- /bin/bash -c "! (test -e /root/yofile || test -L /root/yofile ) || ( stat -c 'user=%U group=%G mode=%A atime=%X mtime=%Y ctime=%Z size=%s %N' /root/yofile 2> /dev/null || stat -f 'user=%Su group=%Sg mode=%Sp atime=%a mtime=%m ctime=%c size=%z %N%SY' /root/yofile )"
user=root group=root mode=-rw-r--r-- atime=1754357120 mtime=1754357120 ctime=1754357120 size=0 '/root/yofile'
2

incus exec runs a binary directly, it doesn’t know what a shell is or which one you may want to use, so you indeed need to run something like incus exec NAME -- bash -c "XYZ" or incus exec NAME -- sh -c "XYZ" to do what you’re describing here.

1 Like
3

Thanks for confirming that @stgraber !