1. Implement pgrep in bash to get rid of procps dependency
2. dump env vars one more time to make sure /build/env-vars includes everything at the point of failure
3. Load env vars via `--init-file /build/env-vars` when executing the interacitve bash session to include bash native variables
4. Use buildPackages for tools used in attach script, to allow usage in cross compiling screnarios
5. use util-linuxMinimal instead of util-linux to get rid of systemd dependency
6. add flags to nsenter: --ipc --uts --pid
4a478ad081