systemd/profile.d/70-systemd-shell-extra.sh

# shellcheck shell=sh

#  This file is part of systemd.
#
#  systemd is free software; you can redistribute it and/or modify it
#  under the terms of the GNU Lesser General Public License as published by
#  the Free Software Foundation; either version 2.1 of the License, or
#  (at your option) any later version.

# Import the additional shell prompt prefix and suffix strings into $PS1, and
# show the shell welcome string. These can be provisioned as system or service
# credentials shell.prompt.prefix, shell.prompt.suffix and shell.welcome, and
# are propagated into these environment variables by pam_systemd(8).

if [ -n "${SHELL_PROMPT_PREFIX-}" ]; then
    PS1="$SHELL_PROMPT_PREFIX$PS1"
fi

if [ -n "${SHELL_PROMPT_SUFFIX-}" ]; then
    PS1="$PS1$SHELL_PROMPT_SUFFIX"
fi

if [ -n "${SHELL_WELCOME-}" ]; then
   printf '%b\n' "$SHELL_WELCOME"
fi
shell: define three system credentials we can propagate into shell prompts and welcome messages 2024-09-06 16:30:54 +02:00			`# shellcheck shell=sh`

			`# This file is part of systemd.`
			`#`
			`# systemd is free software; you can redistribute it and/or modify it`
			`# under the terms of the GNU Lesser General Public License as published by`
			`# the Free Software Foundation; either version 2.1 of the License, or`
			`# (at your option) any later version.`

			`# Import the additional shell prompt prefix and suffix strings into $PS1, and`
			`# show the shell welcome string. These can be provisioned as system or service`
			`# credentials shell.prompt.prefix, shell.prompt.suffix and shell.welcome, and`
			`# are propagated into these environment variables by pam_systemd(8).`

profile.d: don't bail if $SHELL_* variables are unset If - for whatever reason - a script uses set -u (nounset) and includes /etc/profile.d/70-systemd-shell-extra.sh (e.g. transitively via /etc/profile) the script would fail with: /etc/profile.d/70-systemd-shell-extra.sh: line 15: SHELL_PROMPT_PREFIX: unbound variable For example: $ cat > foo.sh <<EOF #!/bin/sh set -u source /etc/profile EOF $ chmod 700 foo.sh $ ./foo.sh /etc/profile.d/70-systemd-shell-extra.sh: line 15: SHELL_PROMPT_PREFIX: unbound variable Fix this by using shell parameter substitution[^1] (which is a POSIX shell concept) to set the $SHELL_* variables to the empty string if undefined. [^1]: https://pubs.opengroup.org/onlinepubs/9699919799.2018edition/utilities/V3_chap02.html 2024-12-11 15:10:39 +01:00			`if [ -n "${SHELL_PROMPT_PREFIX-}" ]; then`
shell: define three system credentials we can propagate into shell prompts and welcome messages 2024-09-06 16:30:54 +02:00			`PS1="$SHELL_PROMPT_PREFIX$PS1"`
			`fi`

profile.d: don't bail if $SHELL_* variables are unset If - for whatever reason - a script uses set -u (nounset) and includes /etc/profile.d/70-systemd-shell-extra.sh (e.g. transitively via /etc/profile) the script would fail with: /etc/profile.d/70-systemd-shell-extra.sh: line 15: SHELL_PROMPT_PREFIX: unbound variable For example: $ cat > foo.sh <<EOF #!/bin/sh set -u source /etc/profile EOF $ chmod 700 foo.sh $ ./foo.sh /etc/profile.d/70-systemd-shell-extra.sh: line 15: SHELL_PROMPT_PREFIX: unbound variable Fix this by using shell parameter substitution[^1] (which is a POSIX shell concept) to set the $SHELL_* variables to the empty string if undefined. [^1]: https://pubs.opengroup.org/onlinepubs/9699919799.2018edition/utilities/V3_chap02.html 2024-12-11 15:10:39 +01:00			`if [ -n "${SHELL_PROMPT_SUFFIX-}" ]; then`
shell: define three system credentials we can propagate into shell prompts and welcome messages 2024-09-06 16:30:54 +02:00			`PS1="$PS1$SHELL_PROMPT_SUFFIX"`
			`fi`

profile.d: don't bail if $SHELL_* variables are unset If - for whatever reason - a script uses set -u (nounset) and includes /etc/profile.d/70-systemd-shell-extra.sh (e.g. transitively via /etc/profile) the script would fail with: /etc/profile.d/70-systemd-shell-extra.sh: line 15: SHELL_PROMPT_PREFIX: unbound variable For example: $ cat > foo.sh <<EOF #!/bin/sh set -u source /etc/profile EOF $ chmod 700 foo.sh $ ./foo.sh /etc/profile.d/70-systemd-shell-extra.sh: line 15: SHELL_PROMPT_PREFIX: unbound variable Fix this by using shell parameter substitution[^1] (which is a POSIX shell concept) to set the $SHELL_* variables to the empty string if undefined. [^1]: https://pubs.opengroup.org/onlinepubs/9699919799.2018edition/utilities/V3_chap02.html 2024-12-11 15:10:39 +01:00			`if [ -n "${SHELL_WELCOME-}" ]; then`
shell: define three system credentials we can propagate into shell prompts and welcome messages 2024-09-06 16:30:54 +02:00			`printf '%b\n' "$SHELL_WELCOME"`
			`fi`