`busybox whoami` is probably fine, but having to write `busybox ls`, `busybox grep`, `busybox cp` etc. would get tedious quickly.
Shell aliases don't solve all problems, even if you do:
alias rm="busybox rm"
alias xargs="busybox xargs"
# etc.
you still have to write `xargs -exec busybox rm`, because xargs won't use the shell alias.
But the main problem with this approach is that POSIX and LSB require certain binaries to be available at certain paths. When they're not, most shell scripts will just break.
The minimal standard solution is probably to create shell scripts for all of these, e.g. in /bin/ls:
#!/bin/sh
exec /bin/busybox ls
But this both adds runtime overhead (on every invocation!) and is quite wasteful in terms of disk space. Busybox boasts over 400 tools. At 4 KB per file, that's 1.6 MiB of just shell scripts. Of course that can be less if the file system uses some type of compression which is common on embedded systems where storage space is small, but it still seems to defeat the purpose of using busybox to create a minimal system.
Actually this observation invalidates the whole setup. Because even though you could define /bin/sh itself as:
#!/bin/busybox sh
exec /bin/busybox sh
Then you still cannot use #!/bin/sh in any other shell scripts, because for historical reasons the interpreter of a script is not allowed to be another interpreted script, it must be a binary. So /bin/sh pretty much has to be an actual binary.
Shell aliases don't solve all problems, even if you do:
you still have to write `xargs -exec busybox rm`, because xargs won't use the shell alias.But the main problem with this approach is that POSIX and LSB require certain binaries to be available at certain paths. When they're not, most shell scripts will just break.
The minimal standard solution is probably to create shell scripts for all of these, e.g. in /bin/ls:
But this both adds runtime overhead (on every invocation!) and is quite wasteful in terms of disk space. Busybox boasts over 400 tools. At 4 KB per file, that's 1.6 MiB of just shell scripts. Of course that can be less if the file system uses some type of compression which is common on embedded systems where storage space is small, but it still seems to defeat the purpose of using busybox to create a minimal system.