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Description of problem:

The following error is shown on login when using ksh as the default shell:

```
/etc/profile[61]: .[293]: export: -f: unknown option
Usage: export [-p] [name[=value]...]
 Help: export [ --help | --man ] 2>&1
```

Version-Release number of selected component (if applicable):

setup-2.13.7-6.el9.noarch
ksh-1.0.0~beta.1-2.el9.x86_64

How reproducible:

happens every time

Steps to Reproduce:
1. sudo dnf -y install ksh
2. sudo usermod -s /bin/ksh93 $(whoami)
3. logout and login again

Actual results:

see above

Expected results:

no "export -f" error, /etc/profile that works with ksh

Additional info:

The root cause is `/etc/profile.d/which2.sh` from package `which-2.21-27.el9.x86_64`:


```bash
[...]
which_opt="-f" # <--
which_shell="$(cat /proc/$$/comm)" # <-- yields ksh93 for ksh93 shell

if [ "$which_shell" = "ksh" ] || [ "$which_shell" = "mksh" ] || [ "$which_shell" = "zsh" ] ; then # "ksh" != "ksh93"
  which_declare="typeset -f"
  which_opt=""
fi

which ()
{
(alias; eval ${which_declare}) | /usr/bin/which --tty-only --read-alias --read-functions --show-tilde --show-dot "$@"
}

export which_declare
export ${which_opt} which
```

I guess the fix would be adding `|| [ "$which_shell" = "ksh93" ]`.

it is fixed in which-2.21-28.el9

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (which bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2022:8305