Consolidate document creation scripts and fix bugs

Replace the individual new_knitr_document, new_tex_assignment, and
new_tex_letter scripts with a single new_tex_document script that takes
a document type as its first argument. Fix bugs present in all scripts:
unquoted variables, TMPDIR name collision, missing existence checks, and
mktemp running unconditionally. Add cdsc_tex_aliases.sh for backwards
compatibility with old script names. Add rename_tex_to_dirname script
(moved from ~/bin). Update README and wiki page to reflect new setup.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

new_tex_document

@@ -1,22 +1,64 @@
 #!/bin/sh
 
-# Helper script to export LaTeX templates for new documents
-# Copyright (c) 2009-2016 Benjamin Mako Hill <mako@atdot.cc>
+# Helper script to export LaTeX/knitr templates for new documents
+# Copyright (c) 2009-2026 Benjamin Mako Hill <mako@atdot.cc>
 # Released under the GPLv3 or later.
 
+set -e
+
 CURDIR=$(pwd)
-TMPDIR=$(mktemp -d)
 
-if test $1
-then
-    cd "$HOME/tex/cdsc_tex"
-    git archive --format=tar master paper_template|tar x --strip=1 -C "$TMPDIR"
-    cd "$CURDIR"
+usage() {
+    echo "Usage: $(basename "$0") <type> <directory>"
+    echo "Types: paper, assignment, knitr, letter"
+    exit 1
+}
 
-    # get rid of paper_template subdir
-    mv "$TMPDIR" "$1"
-    cd "$1";
-    mv "text.tex" "$1.tex"
-else
-    echo "specifiy a directory where the template should go";
+[ -n "$1" ] && [ -n "$2" ] || usage
+
+TYPE="$1"
+DEST="$2"
+
+case "$TYPE" in
+    paper)
+        REPO="$HOME/tex/cdsc_tex"
+        BRANCH="master"
+        TEMPLATE="paper_template"
+        EXT="tex"
+        ;;
+    assignment)
+        REPO="$HOME/tex/cdsc_tex"
+        BRANCH="master"
+        TEMPLATE="assignment_template"
+        EXT="tex"
+        ;;
+    knitr)
+        REPO="$HOME/tex/cdsc_tex"
+        BRANCH="knitr"
+        TEMPLATE="paper_template"
+        EXT="Rtex"
+        ;;
+    letter)
+        REPO="$HOME/tex/cdsc_tex"
+        BRANCH="master"
+        TEMPLATE="letter_template"
+        EXT="tex"
+        ;;
+    *)
+        echo "error: unknown type '$TYPE'"
+        usage
+        ;;
+esac
+
+if [ -e "$DEST" ]; then
+    echo "error: '$DEST' already exists"
+    exit 1
 fi
+
+WORK_DIR=$(mktemp -d)
+cd "$REPO"
+git archive --format=tar "$BRANCH" "$TEMPLATE" | tar x --strip=1 -C "$WORK_DIR"
+cd "$CURDIR"
+mv "$WORK_DIR" "$DEST"
+cd "$DEST"
+mv "text.$EXT" "$(basename "$DEST").$EXT"