diff --git a/scripts/features/raspberry_pi_nextcloud.sh b/scripts/features/raspberry_pi_nextcloud.sh
index 4c18b8a..772dde2 100755
--- a/scripts/features/raspberry_pi_nextcloud.sh
+++ b/scripts/features/raspberry_pi_nextcloud.sh
@@ -545,6 +545,7 @@ EOF
 # Fix Nextcloud Issues
 # =============================================================================
 
+# shellcheck disable=SC2120  # Optional arguments are intentional
 phase_fix_issues() {
   check_root
 
diff --git a/scripts/utils/analyze_repo.sh b/scripts/utils/analyze_repo.sh
index 9dc5f82..e03e447 100755
--- a/scripts/utils/analyze_repo.sh
+++ b/scripts/utils/analyze_repo.sh
@@ -109,7 +109,7 @@ find_files() {
       # Not a git repo - fall back to manual exclusion
       local find_args=()
       for i in "${!patterns[@]}"; do
-        if [ $i -eq 0 ]; then
+        if [ "$i" -eq 0 ]; then
           find_args+=(-name "${patterns[$i]}")
         else
           find_args+=(-o -name "${patterns[$i]}")
@@ -121,7 +121,7 @@ find_files() {
     # No filtering - find all files
     local find_args=()
     for i in "${!patterns[@]}"; do
-      if [ $i -eq 0 ]; then
+      if [ "$i" -eq 0 ]; then
         find_args+=(-name "${patterns[$i]}")
       else
         find_args+=(-o -name "${patterns[$i]}")
@@ -298,7 +298,7 @@ if [ "$RESPECT_GITIGNORE" = true ] && is_git_repo; then
   } | sort -u | wc -l)
   echo "Files: $FILE_COUNT (respecting .gitignore)"
 elif [ "$RESPECT_GITIGNORE" = true ]; then
-  echo "Files: $(find . -type f 2> /dev/null | grep -Ev "/($EXCLUDE_DIRS)/" | wc -l) (excluding common dirs)"
+  echo "Files: $(find . -type f 2> /dev/null | grep -cEv "/($EXCLUDE_DIRS)/") (excluding common dirs)"
 else
   echo "Files: $(find . -type f | wc -l)"
 fi
@@ -332,7 +332,7 @@ print_header "STEP 4: Fast Keyword Analysis (Code vs Comments)"
 fast_count() {
   local top_n="${1:-50}"
   if command -v counts &> /dev/null; then
-    counts 2> /dev/null | head -$((top_n + 1)) | tail -$top_n
+    counts 2> /dev/null | head -$((top_n + 1)) | tail -"$top_n"
   else
     python3 -c "
 import sys
@@ -389,14 +389,14 @@ HAS_GO=false
 HAS_RUST=false
 HAS_JAVA=false
 
-((${LANG_FILES[c]} + ${LANG_FILES[cpp]} + ${LANG_FILES[h]} > 0)) && HAS_C_FAMILY=true
-((${LANG_FILES[python]} > 0)) && HAS_PYTHON=true
-((${LANG_FILES[javascript]} + ${LANG_FILES[typescript]} > 0)) && HAS_JS_FAMILY=true
-((${LANG_FILES[shell]} > 0)) && HAS_SHELL=true
-((${LANG_FILES[ruby]} > 0)) && HAS_RUBY=true
-((${LANG_FILES[go]} > 0)) && HAS_GO=true
-((${LANG_FILES[rust]} > 0)) && HAS_RUST=true
-((${LANG_FILES[java]} > 0)) && HAS_JAVA=true
+((LANG_FILES[c] + LANG_FILES[cpp] + LANG_FILES[h] > 0)) && HAS_C_FAMILY=true
+((LANG_FILES[python] > 0)) && HAS_PYTHON=true
+((LANG_FILES[javascript] + LANG_FILES[typescript] > 0)) && HAS_JS_FAMILY=true
+((LANG_FILES[shell] > 0)) && HAS_SHELL=true
+((LANG_FILES[ruby] > 0)) && HAS_RUBY=true
+((LANG_FILES[go] > 0)) && HAS_GO=true
+((LANG_FILES[rust] > 0)) && HAS_RUST=true
+((LANG_FILES[java] > 0)) && HAS_JAVA=true
 
 #------------------------------------------------------------------------------
 # Language-specific keyword definitions
@@ -718,7 +718,9 @@ ugrep -o '\b[a-zA-Z_][a-zA-Z0-9_]*\b' "$COMMENTS_TEMP" 2> /dev/null |
 # List what per-language files were created
 echo ""
 echo "Per-language analysis files created:"
-ls -la "$RESULTS_DIR/per_language/" 2> /dev/null | grep -v '^total' | awk '{print "  " $NF}'
+if [ -d "$RESULTS_DIR/per_language/" ]; then
+  find "$RESULTS_DIR/per_language/" -maxdepth 1 -type f -printf "  %f\n" 2> /dev/null | sort
+fi
 
 print_subheader "Generating tags (this may take a while)..."
 
@@ -737,7 +739,7 @@ if [ -f "$RESULTS_DIR/tags" ]; then
 
   print_subheader "Symbol Types Distribution"
   # Fast: extract single-letter kind code after ;" and count
-  grep -aoP ';"\t\K[a-z]' "$RESULTS_DIR/tags" 2> /dev/null | fast_count 20 | while read count kind; do
+  grep -aoP ';"\t\K[a-z]' "$RESULTS_DIR/tags" 2> /dev/null | fast_count 20 | while read -r count kind; do
     case $kind in
       f) echo "$count functions" ;;
       v) echo "$count variables" ;;
diff --git a/scripts/utils/android_guardian/service.sh b/scripts/utils/android_guardian/service.sh
index 8729326..f58bec8 100755
--- a/scripts/utils/android_guardian/service.sh
+++ b/scripts/utils/android_guardian/service.sh
@@ -79,7 +79,11 @@ check_blocked_apps() {
     # Check if package is installed
     if pm list packages 2> /dev/null | grep -q "package:$package"; then
       log "Blocked app detected: $package - Uninstalling..."
-      pm uninstall "$package" 2> /dev/null && log "Uninstalled: $package" || log "Failed to uninstall: $package"
+      if pm uninstall "$package" 2> /dev/null; then
+        log "Uninstalled: $package"
+      else
+        log "Failed to uninstall: $package"
+      fi
     fi
   done < "$BLOCKED_APPS_FILE"
 }
diff --git a/scripts/utils/download_exercism_bulk.sh b/scripts/utils/download_exercism_bulk.sh
index 3ee3112..869ba83 100755
--- a/scripts/utils/download_exercism_bulk.sh
+++ b/scripts/utils/download_exercism_bulk.sh
@@ -64,7 +64,9 @@ for track in "${!TRACKS[@]}"; do
 
   # Show exercise count
   if [[ -d "$track/exercises/practice" ]]; then
-    count=$(ls "$track/exercises/practice" | wc -l)
+    count=$(find "$track/exercises/practice" -maxdepth 1 -type d | wc -l)
+    # Subtract 1 for the parent directory itself
+    count=$((count - 1))
     echo "    → $count practice exercises available"
   fi
   echo ""
@@ -100,7 +102,9 @@ echo ""
 echo "Track summary:"
 for track in "${!TRACKS[@]}"; do
   if [[ -d "$track/exercises/practice" ]]; then
-    count=$(ls "$track/exercises/practice" 2> /dev/null | wc -l)
+    count=$(find "$track/exercises/practice" -maxdepth 1 -type d 2> /dev/null | wc -l)
+    # Subtract 1 for the parent directory itself
+    count=$((count - 1))
     printf "  %-15s %3d exercises\n" "$track" "$count"
   fi
 done | sort
diff --git a/scripts/utils/generate_study_materials.sh b/scripts/utils/generate_study_materials.sh
index 63b3c62..dea352e 100755
--- a/scripts/utils/generate_study_materials.sh
+++ b/scripts/utils/generate_study_materials.sh
@@ -96,7 +96,6 @@ lookup_offline() {
 # Python documentation
 python_doc_url() {
   local term="$1"
-  local type="$2" # keyword, builtin, module
 
   case "$term" in
     # Keywords
@@ -333,14 +332,14 @@ shell_doc_url() {
 
   case "$term" in
     # Built-in commands
-    if | then | else | elif | fi | for | while | until | do | done | case | esac | in | function | select | time | coproc)
+    if | then | else | elif | fi | for | while | until | do | done | case | 'esac' | in | function | select | time | coproc)
       echo "https://www.gnu.org/software/bash/manual/bash.html#Conditional-Constructs"
       ;;
     echo | printf | read | declare | local | export | unset | set | shopt | alias | source | eval | exec | exit | return | break | continue | shift | trap | wait | kill | jobs | bg | fg | disown | suspend | logout | cd | pwd | pushd | popd | dirs | type | which | command | builtin | enable | help | hash | bind | complete | compgen | compopt)
       echo "https://www.gnu.org/software/bash/manual/bash.html#Shell-Builtin-Commands"
       ;;
     # Common external commands
-    grep | sed | awk | find | xargs | sort | uniq | cut | tr | head | tail | wc | cat | tee | diff | patch | tar | gzip | zip | curl | wget | ssh | scp | rsync | git | make | chmod | chown | chgrp | ln | cp | mv | rm | mkdir | rmdir | touch | ls | stat | file | df | du | free | top | ps | kill | pkill | pgrep | nohup | screen | tmux)
+    grep | sed | awk | find | xargs | sort | uniq | cut | tr | head | tail | wc | cat | tee | diff | patch | tar | gzip | zip | curl | wget | ssh | scp | rsync | git | make | chmod | chown | chgrp | ln | cp | mv | rm | mkdir | rmdir | touch | ls | stat | file | df | du | free | top | ps | pkill | pgrep | nohup | screen | tmux)
       echo "https://man7.org/linux/man-pages/man1/$term.1.html"
       ;;
     *)
@@ -528,7 +527,7 @@ if [ -d "$PER_LANG_DIR" ]; then
     echo "| Keyword | Count | Documentation |" >> "$DOCS_FILE"
     echo "|---------|-------|---------------|" >> "$DOCS_FILE"
 
-    head -$TOP_N "$keyword_file" | while read -r count term; do
+    head -"$TOP_N" "$keyword_file" | while read -r count term; do
       [ -z "$term" ] && continue
       [[ $term =~ ^[#] ]] && continue # Skip comment lines
       url=$(get_doc_url "$term" "$doc_lang")
@@ -566,7 +565,7 @@ if [ -d "$PER_LANG_DIR" ]; then
     echo "| Function | Count | Documentation |" >> "$DOCS_FILE"
     echo "|----------|-------|---------------|" >> "$DOCS_FILE"
 
-    head -$TOP_N "$func_file" | while read -r count term; do
+    head -"$TOP_N" "$func_file" | while read -r count term; do
       [ -z "$term" ] && continue
       [[ $term =~ ^(if|for|while|switch|catch|elif)$ ]] && continue
       url=$(get_doc_url "$term" "$doc_lang")
@@ -613,7 +612,7 @@ if [ -d "$PER_LANG_DIR" ]; then
         module=$(echo "$import" | sed -E 's/.*[<"]([^">]+)[">].*/\1/' | sed 's|.*/||' | sed 's/\..*$//')
         url=$(get_doc_url "$module" "$doc_lang")
       fi
-      import_escaped=$(echo "$import" | sed 's/|/\\|/g')
+      import_escaped="${import//|/\\|}"
       echo "| \`$import_escaped\` | $count | [docs]($url) |" >> "$DOCS_FILE"
     done
     echo "" >> "$DOCS_FILE"
@@ -629,7 +628,7 @@ else
     echo "| Keyword | Count | Documentation |" >> "$DOCS_FILE"
     echo "|---------|-------|---------------|" >> "$DOCS_FILE"
 
-    head -$TOP_N "$RESULTS_DIR/grep_keywords.txt" | while read -r count term; do
+    head -"$TOP_N" "$RESULTS_DIR/grep_keywords.txt" | while read -r count term; do
       [ -z "$term" ] && continue
       url=$(get_doc_url "$term" "$PRIMARY_LANG")
       echo "| \`$term\` | $count | [docs]($url) |" >> "$DOCS_FILE"
@@ -643,7 +642,7 @@ else
     echo "| Function | Count | Documentation |" >> "$DOCS_FILE"
     echo "|----------|-------|---------------|" >> "$DOCS_FILE"
 
-    head -$TOP_N "$RESULTS_DIR/grep_function_calls.txt" | while read -r count term; do
+    head -"$TOP_N" "$RESULTS_DIR/grep_function_calls.txt" | while read -r count term; do
       [ -z "$term" ] && continue
       [[ $term =~ ^(if|for|while|switch|catch)$ ]] && continue
       url=$(get_doc_url "$term" "$PRIMARY_LANG")
@@ -662,7 +661,7 @@ else
       [ -z "$import" ] && continue
       module=$(echo "$import" | sed -E 's/.*[<"]([^">]+)[">].*/\1/' | sed 's|.*/||' | sed 's/\..*$//')
       url=$(get_doc_url "$module" "$PRIMARY_LANG")
-      import_escaped=$(echo "$import" | sed 's/|/\\|/g')
+      import_escaped="${import//|/\\|}"
       echo "| \`$import_escaped\` | $count | [docs]($url) |" >> "$DOCS_FILE"
     done
     echo "" >> "$DOCS_FILE"
@@ -694,7 +693,7 @@ EOF
 # Generate cards for top keywords
 if [ -f "$RESULTS_DIR/grep_keywords.txt" ]; then
   echo "# Keywords" >> "$ANKI_FILE"
-  head -$TOP_N "$RESULTS_DIR/grep_keywords.txt" | while read -r count term; do
+  head -"$TOP_N" "$RESULTS_DIR/grep_keywords.txt" | while read -r count term; do
     [ -z "$term" ] && continue
     url=$(get_doc_url "$term" "$PRIMARY_LANG")
 
@@ -732,7 +731,7 @@ fi
 if [ -f "$RESULTS_DIR/grep_function_calls.txt" ]; then
   echo "" >> "$ANKI_FILE"
   echo "# Functions" >> "$ANKI_FILE"
-  head -$TOP_N "$RESULTS_DIR/grep_function_calls.txt" | while read -r count term; do
+  head -"$TOP_N" "$RESULTS_DIR/grep_function_calls.txt" | while read -r count term; do
     [ -z "$term" ] && continue
     [[ $term =~ ^(if|for|while|switch|catch)$ ]] && continue
     url=$(get_doc_url "$term" "$PRIMARY_LANG")
@@ -780,11 +779,14 @@ generate_keywords_with_docs() {
   local keywords_file="$RESULTS_DIR/grep_keywords.txt"
   [ ! -f "$keywords_file" ] && echo "No keywords found" && return
 
-  head -$TOP_N "$keywords_file" | grep -v '^#' | while read -r line; do
-    local count=$(echo "$line" | awk '{print $1}')
-    local keyword=$(echo "$line" | awk '{print $2}')
+  head -"$TOP_N" "$keywords_file" | grep -v '^#' | while read -r line; do
+    local count
+    local keyword
+    local doc_link
+    count=$(echo "$line" | awk '{print $1}')
+    keyword=$(echo "$line" | awk '{print $2}')
     [ -z "$keyword" ] && continue
-    local doc_link=$(get_llm_doc_link "$keyword" "$PRIMARY_LANG" "false")
+    doc_link=$(get_llm_doc_link "$keyword" "$PRIMARY_LANG" "false")
     echo "$count $keyword → $doc_link"
   done
 }
@@ -794,16 +796,19 @@ generate_functions_with_docs() {
   local functions_file="$RESULTS_DIR/grep_function_calls.txt"
   [ ! -f "$functions_file" ] && echo "No functions found" && return
 
-  head -$TOP_N "$functions_file" | grep -v '^#' | while read -r line; do
-    local count=$(echo "$line" | awk '{print $1}')
-    local func=$(echo "$line" | awk '{print $2}')
+  head -"$TOP_N" "$functions_file" | grep -v '^#' | while read -r line; do
+    local count
+    local func
+    local doc_link
+    count=$(echo "$line" | awk '{print $1}')
+    func=$(echo "$line" | awk '{print $2}')
 
     # Skip single-letter functions (minified code) or empty
     if [ -z "$func" ] || [ ${#func} -le 1 ]; then
       continue
     fi
 
-    local doc_link=$(get_llm_doc_link "$func" "$PRIMARY_LANG" "false")
+    doc_link=$(get_llm_doc_link "$func" "$PRIMARY_LANG" "false")
     echo "$count $func() → $doc_link"
   done
 }
@@ -814,15 +819,18 @@ generate_imports_with_docs() {
   [ ! -f "$imports_file" ] && echo "No imports found" && return
 
   head -20 "$imports_file" | grep -v '^#' | while read -r line; do
-    local count=$(echo "$line" | awk '{print $1}')
-    local import_stmt=$(echo "$line" | cut -d' ' -f2-)
+    local count
+    local import_stmt
+    local doc_link
+    count=$(echo "$line" | awk '{print $1}')
+    import_stmt=$(echo "$line" | cut -d' ' -f2-)
     [ -z "$import_stmt" ] && continue
 
     # Check if internal import
     if [[ $import_stmt =~ @/ ]] || [[ $import_stmt =~ \'\./ ]] || [[ $import_stmt =~ from\ app\. ]] || [[ $import_stmt =~ from\ src\. ]]; then
       echo "$count $import_stmt → [INTERNAL - SKIP]"
     else
-      local doc_link=$(get_llm_doc_link "$import_stmt" "$PRIMARY_LANG" "true")
+      doc_link=$(get_llm_doc_link "$import_stmt" "$PRIMARY_LANG" "true")
       echo "$count $import_stmt → $doc_link"
     fi
   done
diff --git a/scripts/utils/install_exercism.sh b/scripts/utils/install_exercism.sh
index 078a108..4fa2237 100755
--- a/scripts/utils/install_exercism.sh
+++ b/scripts/utils/install_exercism.sh
@@ -110,7 +110,7 @@ install_exercism_cli() {
   # Check PATH
   if [[ ":$PATH:" != *":$HOME/.local/bin:"* ]]; then
     warn "Add ~/.local/bin to your PATH:"
-    echo '  export PATH="$HOME/.local/bin:$PATH"'
+    echo "  export PATH=\"\$HOME/.local/bin:\$PATH\""
   fi
 }
 
@@ -151,7 +151,11 @@ install_test_runners() {
       success "Python: pytest already installed"
     else
       info "Installing pytest for Python exercises..."
-      pip3 install --user pytest 2> /dev/null && success "Python: pytest installed" || warn "Python: install pytest manually"
+      if pip3 install --user pytest 2> /dev/null; then
+        success "Python: pytest installed"
+      else
+        warn "Python: install pytest manually"
+      fi
     fi
   fi
 
@@ -256,8 +260,8 @@ show_usage() {
   echo ""
   echo -e "${CYAN}Batch download (requires API token):${NC}"
   echo "  # Download first 20 Python exercises:"
-  echo '  for ex in $(exercism download --track=python 2>&1 | head -20); do'
-  echo '    exercism download --track=python --exercise=$ex'
+  echo "  for ex in \$(exercism download --track=python 2>&1 | head -20); do"
+  echo "    exercism download --track=python --exercise=\$ex"
   echo "  done"
   echo ""
   echo "Exercises are in: $EXERCISM_DIR"
diff --git a/scripts/utils/install_plagiarism_tools.sh b/scripts/utils/install_plagiarism_tools.sh
index 1de0b64..7149803 100755
--- a/scripts/utils/install_plagiarism_tools.sh
+++ b/scripts/utils/install_plagiarism_tools.sh
@@ -521,12 +521,12 @@ echo "  plagcheck thesis_v1.pdf thesis_v2.pdf --detailed"
 echo "  plagcheck --dir ./student_papers/ --threshold 0.4"
 echo ""
 echo "Note: Ensure ~/.local/bin is in your PATH:"
-echo '  export PATH="$HOME/.local/bin:$PATH"'
+echo "  export PATH=\"\$HOME/.local/bin:\$PATH\""
 echo ""
 echo "=============================================="
 
 # Add to PATH reminder
 if [[ ":$PATH:" != *":$HOME/.local/bin:"* ]]; then
   warn "Add ~/.local/bin to your PATH by adding this to ~/.bashrc or ~/.zshrc:"
-  echo '  export PATH="$HOME/.local/bin:$PATH"'
+  echo "  export PATH=\"\$HOME/.local/bin:\$PATH\""
 fi
diff --git a/scripts/utils/lookup_docs.sh b/scripts/utils/lookup_docs.sh
index 80a2df9..840a22c 100755
--- a/scripts/utils/lookup_docs.sh
+++ b/scripts/utils/lookup_docs.sh
@@ -887,7 +887,7 @@ main() {
       if [ "$lang" = "all" ]; then
         lookup_all "$term"
       else
-        result=$(lookup_$lang "$term" 2> /dev/null)
+        result=$(lookup_"$lang" "$term" 2> /dev/null)
         if [ -n "$result" ]; then
           local file desc
           file=$(echo "$result" | cut -d'|' -f1)
diff --git a/scripts/utils/repo_to_study.sh b/scripts/utils/repo_to_study.sh
index 85a14ed..d67084c 100755
--- a/scripts/utils/repo_to_study.sh
+++ b/scripts/utils/repo_to_study.sh
@@ -30,7 +30,6 @@ STUDY_MATERIALS_BASE="$HOME/.local/share/study-materials"
 
 # Work directories
 WORK_DIR="/tmp/repo_study_$$"
-OUTPUT_DIR=""
 
 # Colors
 RED='\033[0;31m'
diff --git a/scripts/utils/update_android_hosts.sh b/scripts/utils/update_android_hosts.sh
index 47f7f6c..9f8861a 100755
--- a/scripts/utils/update_android_hosts.sh
+++ b/scripts/utils/update_android_hosts.sh
@@ -25,7 +25,10 @@ ensure_adb_installed() {
   if command -v pacman &> /dev/null; then
     sudo pacman -S --noconfirm android-tools || die "Failed to install android-tools"
   elif command -v apt-get &> /dev/null; then
-    sudo apt-get update && sudo apt-get install -y adb || die "Failed to install adb"
+    if ! sudo apt-get update; then
+      die "Failed to update package lists"
+    fi
+    sudo apt-get install -y adb || die "Failed to install adb"
   elif command -v dnf &> /dev/null; then
     sudo dnf install -y android-tools || die "Failed to install android-tools"
   else