Adjust locale settings for local usage

.config/shell/locale

@@ -1,24 +1,42 @@
 #!/bin/sh
 
-# Locale settings for headless machines
+# Locale settings for desktop machines
+# as run by the author of this `dotfiles` repository
+
+# Requires the en_US.UTF-8, en_DK.UTF-8, en_IE.UTF-8, and de_DE.UTF-8
+# locales be installed which is checked by ~/.local/bin/ensure-locales
+
+# Other hosts (e.g., servers) usually lack some of these locales,
+# and Debian's /etc/ssh/ssh_config forwards all of them via `SendEnv LANG LC_*`
+# => ~/.local/bin/ssh, ~/.local/bin/scp, and ~/.local/bin/sftp
+#    send `LC_ALL=C.UTF-8` on top to mask them on remote hosts
 
 
-# Drop what a client may forward over `ssh`,
-# because `AcceptEnv LANG LC_*` may be set in /etc/ssh/sshd_config
-unset \
-    LC_ALL \
-    LC_ADDRESS \
-    LC_COLLATE \
-    LC_CTYPE LC_IDENTIFICATION \
-    LC_MEASUREMENT \
-    LC_MESSAGES \
-    LC_MONETARY \
-    LC_NAME \
-    LC_NUMERIC \
-    LC_PAPER \
-    LC_TELEPHONE \
-    LC_TIME
+export LANG=en_US.UTF-8               # Fallback for any (future) LC_* not set below
 
 
-# Set every LC_* category implicitly with the `$LANG` fallback
-export LANG=C.UTF-8
+# Base: US English for language, text handling, and sorting
+
+export LC_COLLATE=en_US.UTF-8         # Dictionary sort order => Ignore punctuation
+export LC_CTYPE=en_US.UTF-8           # UTF-8 character classification
+export LC_MESSAGES=en_US.UTF-8
+export LC_NUMERIC=en_US.UTF-8         # 1,234.56 rather than 1.234,56
+
+
+# Exceptions: European conventions with English number formatting
+
+export LC_MEASUREMENT=en_IE.UTF-8     # Use the metric system
+export LC_MONETARY=en_IE.UTF-8        # Euro with 1,234.56
+export LC_PAPER=en_IE.UTF-8           # Use DIN-A4 for a page
+export LC_TIME=en_DK.UTF-8            # ISO dates, 24h clock, Monday first
+
+
+# (German) metadata
+
+export LC_ADDRESS=de_DE.UTF-8         # German postal layout
+export LC_IDENTIFICATION=en_US.UTF-8
+export LC_NAME=en_US.UTF-8
+export LC_TELEPHONE=de_DE.UTF-8       # For "+49" and "030 12345"
+
+
+export TZ="Europe/Berlin"

.local/bin/dotfiles-install

@@ -143,6 +143,10 @@ done
 unset _key
 
 
+locales_ok=1
+sh "$XDG_BIN_HOME/ensure-locales" >/dev/null 2>&1 || locales_ok=0
+
+
 if command -v batcat >/dev/null 2>&1 && ! command -v bat >/dev/null 2>&1; then
     ln -sf "$(command -v batcat)" "$XDG_BIN_HOME/bat"
 fi
@@ -191,6 +195,13 @@ fi
 echo ""
 echo "The dotfiles were installed successfully (branch: $DOTFILES_BRANCH)"
 echo ""
+
+if [ "$locales_ok" -ne 1 ]; then
+    echo "WARNING: Some locales are missing, fix:"
+    echo "    sudo $XDG_BIN_HOME/ensure-locales"
+    echo ""
+fi
+
 echo "Reload your shell to use them:"
 echo "    exec \$SHELL -l"
 echo ""

.local/bin/ensure-locales

@@ -0,0 +1,112 @@
+#!/bin/sh
+
+# Ensure all locales specified in ~/.config/shell/locale are installed
+
+set -eu
+
+
+
+LOCALES="en_US.UTF-8 de_DE.UTF-8 en_DK.UTF-8 en_IE.UTF-8"
+
+
+
+# Because `locale -a` prints, for example, "en_US.utf8",
+# and `locale.gen` wants "en_US.UTF-8" instead
+_locale_present() {
+    norm=$(printf '%s' "$1" | tr 'A-Z' 'a-z' | tr -d '-')
+    locale -a 2>/dev/null | tr 'A-Z' 'a-z' | tr -d '-' | grep -qx "$norm"
+}
+
+
+
+# In most cases there should be no missing `$LOCALES`
+
+missing=""
+
+for l in $LOCALES; do
+    _locale_present "$l" || missing="$missing $l"
+done
+
+if [ -z "$missing" ]; then
+    echo ""
+    echo "All locales present"
+    echo ""
+
+    exit 0
+fi
+
+
+
+# If there are missing `$LOCALES`, just notify the user
+# because this script most likely was run as part of `dotfiles-install`
+# and therefore without root privileges
+
+if [ "$(id -u)" != 0 ]; then
+
+    self=$(cd "$(dirname "$0")" && pwd)/$(basename "$0")
+
+    echo "" >&2
+    echo "Missing locales:$missing" >&2
+    echo "" >&2
+    echo "Fix with: sudo $self" >&2
+    echo "" >&2
+
+    exit 1
+
+fi
+
+
+
+# Install the missing `$LOCALES`
+
+if ! command -v locale-gen >/dev/null 2>&1; then
+
+    echo "" >&2
+    echo "locale-gen not found, generate manually:" >&2
+    echo "" >&2
+
+    for l in $missing; do
+        echo "  localedef -i ${l%.*} -f UTF-8 $l" >&2
+    done
+
+    echo "" >&2
+
+    exit 1
+
+fi
+
+
+[ -f /etc/locale.gen ] || : > /etc/locale.gen
+
+
+for l in $missing; do
+
+    # Uncomment existing line, or append if not present at all
+
+    esc=$(printf '%s' "$l" | sed 's/\./\\./g')
+
+    if grep -qE "^#? *$esc UTF-8" /etc/locale.gen; then
+        sed -i "s/^# *\($esc UTF-8\)/\1/" /etc/locale.gen
+    else
+        printf '%s UTF-8\n' "$l" >> /etc/locale.gen
+    fi
+
+done
+
+
+locale-gen
+
+
+
+# verify all missing `$LOCALES` were installed
+
+rc=0
+
+for l in $missing; do
+    _locale_present "$l" || {
+        echo "Failed to generate: $l" >&2;
+        rc=1;
+    }
+done
+
+exit $rc

.local/bin/scp

@@ -0,0 +1,5 @@
+#!/bin/sh
+
+# See ~/.local/bin/ssh
+
+exec /usr/bin/scp -o SetEnv=LC_ALL=C.UTF-8 "$@"

.local/bin/sftp

@@ -0,0 +1,5 @@
+#!/bin/sh
+
+# See ~/.local/bin/ssh
+
+exec /usr/bin/sftp -o SetEnv=LC_ALL=C.UTF-8 "$@"

.local/bin/ssh

@@ -0,0 +1,14 @@
+#!/bin/sh
+
+# Mask the exotic `LC_*` values from ~/.config/shell/locale on remote hosts
+#
+# Debian's /etc/ssh/ssh_config forwards them via `SendEnv LANG LC_*`,
+# which cannot be cleared from ~/.ssh/config
+# => Send `LC_ALL` on top, which overrides all `LC_*` and `LANG` remotely
+#
+# `C.UTF-8` is built into `glibc` and thus available on every host
+#
+# Found via the `$PATH` by `git`, `rsync`, `sshfs`, scripts, and GUI apps;
+# `scp` and `sftp` call /usr/bin/ssh directly and have their own wrappers
+
+exec /usr/bin/ssh -o SetEnv=LC_ALL=C.UTF-8 "$@"