diff --git a/.bashrc b/.bashrc
index c2a2883..e191d2a 100644
--- a/.bashrc
+++ b/.bashrc
@@ -217,6 +217,15 @@ alias ping='ping -c 10'
 alias less='less -R'
 alias cls='clear'
 
+# Debian-family bat packages expose batcat; other platforms normally expose bat.
+# Keep paging disabled, but retain bat's header, grid, and line numbers so plain
+# text files are visibly rendered by bat in an interactive terminal.
+if command -v batcat >/dev/null 2>&1; then
+	alias cat='batcat --paging=never --style=full'
+elif command -v bat >/dev/null 2>&1; then
+	alias cat='bat --paging=never --style=full'
+fi
+
 if command -v trash-put >/dev/null 2>&1; then
 	alias rm='trash-put'
 elif command -v trash >/dev/null 2>&1; then
diff --git a/.github/workflows/bashtest.yml b/.github/workflows/bashtest.yml
index feb23a9..666a58b 100644
--- a/.github/workflows/bashtest.yml
+++ b/.github/workflows/bashtest.yml
@@ -26,6 +26,9 @@ jobs:
       if: steps.cache-shellcheck.outputs.cache-hit != 'true'
       run: sudo apt-get install -y shellcheck
 
+    - name: Install rendering test dependency
+      run: sudo apt-get install -y bat
+
     - name: Lint Bash scripts
       run: |
         echo "Running ShellCheck..."
@@ -36,3 +39,6 @@ jobs:
         else
           echo "No linting errors found."
         fi
+
+    - name: Test shell integration
+      run: tests/test_shell_integration.sh
diff --git a/README.md b/README.md
index f906cfe..b815d25 100644
--- a/README.md
+++ b/README.md
@@ -37,14 +37,14 @@ The `setup.sh` script automates the installation process by:
 - Installing Homebrew on macOS if it is not already installed
 - Installing Bash 5 with Homebrew on macOS
 - Adding Homebrew Bash to `/etc/shells` and setting it as the default login shell on macOS
-- Installing dependencies (bash-completion, neovim, starship, fzf, zoxide)
+- Installing dependencies (bash-completion, bat, neovim, starship, fzf, zoxide)
 - Installing Starship and JetBrainsMono Nerd Font on Linux
 - Selecting JetBrainsMono Nerd Font in Ptyxis or GNOME Terminal when available
 - Installing the MesloLGS Nerd Font required for the prompt on macOS when available
 - Linking configuration files from `~/.local/share/mybash` to your home directory
 - Linking the fastfetch config to `~/.config/fastfetch/config.jsonc`
 - Ensuring `~/.bash_profile` initializes Homebrew on macOS
-- Ensuring `~/.bash_profile` sources `~/.bashrc` on macOS
+- Ensuring the active Bash login profile sources `~/.bashrc` on Linux and macOS
 - Setting up additional utilities like `fastfetch`
 
 On macOS, `setup.sh` may prompt for your password when it adds Homebrew Bash to `/etc/shells` and changes your default shell. Restart Terminal after installation, then verify with:
@@ -103,6 +103,7 @@ The `.bashrc` file defines aliases, functions, and environment variables to enha
 
 - **Aliases**: Shortcuts for common commands (e.g., `alias cp='cp -i'`)
 - **Functions**: Custom functions for tasks like extracting archives and copying files with progress
+- **Enhanced `cat` output**: Interactive shells use `batcat --paging=never --style=full` on Debian-family systems, or `bat` with the same options elsewhere. This preserves bat's header, grid, line numbers, and terminal colors. Non-interactive scripts keep the normal `cat`; use `command cat` to bypass the alias interactively.
 
 ### `starship.toml`
 
@@ -132,6 +133,7 @@ The `config.jsonc` file configures [fastfetch](https://github.com/AlexRogalskiy/
 
 3. **Enhancements and Utilities**
    - Improves command output readability with colors
+   - Uses `batcat` or `bat` for interactive `cat` output without changing non-interactive script behavior
    - Introduces safer file operations (e.g., using `trash` instead of `rm`)
    - Integrates Zoxide for easy directory navigation
 
diff --git a/setup.sh b/setup.sh
index bcf1345..7edb065 100755
--- a/setup.sh
+++ b/setup.sh
@@ -325,21 +325,49 @@ link_file() {
 	print_colored "$GREEN" "Linked $target"
 }
 
-ensure_bash_profile_sources_bashrc() {
-	[ "$OS_NAME" = Darwin ] || return 0
+ensure_login_profile_sources_bashrc() {
+	if [ -f "$HOME/.bash_profile" ]; then
+		profile=$HOME/.bash_profile
+	elif [ -f "$HOME/.bash_login" ]; then
+		profile=$HOME/.bash_login
+	elif [ "$OS_NAME" = Darwin ]; then
+		profile=$HOME/.bash_profile
+	else
+		profile=$HOME/.profile
+	fi
 
-	profile=$HOME/.bash_profile
-	if [ -f "$profile" ] && grep -q 'HOME/.bashrc' "$profile"; then
+	if [ -f "$profile" ] && grep -Eq '^[[:space:]]*(\.|source)[[:space:]]+"?(\$\{?HOME\}?|~)/\.bashrc"?[[:space:]]*($|#)' "$profile"; then
 		return 0
 	fi
 
 	{
-		printf '\n# Source .bashrc for interactive bash shells\n'
-		printf '%s\n' "if [ -f \"\$HOME/.bashrc\" ]; then"
+		printf '\n# >>> mybash .bashrc >>>\n'
+		printf '%s\n' "if [ -n \"\${BASH_VERSION:-}\" ] && [ -f \"\$HOME/.bashrc\" ]; then"
 		printf '%s\n' ". \"\$HOME/.bashrc\""
 		printf 'fi\n'
+		printf '# <<< mybash .bashrc <<<\n'
 	} >>"$profile"
-	print_colored "$GREEN" "Updated $profile to source .bashrc"
+	print_colored "$GREEN" "Updated $profile to source .bashrc in login shells"
+}
+
+verify_interactive_cat_alias() {
+	if command_exists batcat; then
+		expected="batcat --paging=never --style=full"
+	elif command_exists bat; then
+		expected="bat --paging=never --style=full"
+	else
+		print_colored "$RED" "bat was installed, but neither batcat nor bat is available in PATH."
+		return 1
+	fi
+
+	alias_output=$(bash --login -ic 'alias cat >&3' 3>&1 >/dev/null 2>/dev/null || true)
+	expected_output="alias cat='$expected'"
+	if [ "$alias_output" = "$expected_output" ]; then
+		print_colored "$GREEN" "Verified interactive cat alias: $expected"
+	else
+		print_colored "$RED" "The interactive cat alias was not loaded from $HOME/.bashrc."
+		return 1
+	fi
 }
 
 ensure_bash_profile_brew_shellenv() {
@@ -378,13 +406,16 @@ install_configs() {
 	link_file "$MYBASHDIR/starship-theme" "$HOME/.local/bin/starship-theme"
 	ensure_homebrew_bash_macos
 	ensure_bash_profile_brew_shellenv
-	ensure_bash_profile_sources_bashrc
+	ensure_login_profile_sources_bashrc
+	verify_interactive_cat_alias
 }
 
-install_dependencies
-install_starship_linux
-install_nerd_font_linux
-install_configs
-configure_terminal_font_linux
+if [ "${MYBASH_SETUP_LIB_ONLY:-0}" -eq 0 ]; then
+	install_dependencies
+	install_starship_linux
+	install_nerd_font_linux
+	install_configs
+	configure_terminal_font_linux
 
-print_colored "$GREEN" "Installation complete. Restart your shell or run: source ~/.bashrc"
+	print_colored "$GREEN" "Installation complete. Restart your shell or run: source ~/.bashrc"
+fi
diff --git a/tests/test_shell_integration.sh b/tests/test_shell_integration.sh
new file mode 100755
index 0000000..e5c89e4
--- /dev/null
+++ b/tests/test_shell_integration.sh
@@ -0,0 +1,107 @@
+#!/usr/bin/env bash
+# shellcheck disable=SC2030,SC2031 # HOME changes are intentionally isolated in test subshells.
+set -euo pipefail
+
+ROOT=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")/.." && pwd -P)
+fail() { printf 'FAIL: %s\n' "$*" >&2; exit 1; }
+TMPDIR=$(mktemp -d)
+trap 'rm -rf "$TMPDIR"' EXIT
+
+grep -Fq "alias cat='batcat --paging=never --style=full'" "$ROOT/.bashrc" || fail 'missing batcat alias'
+grep -Fq "alias cat='bat --paging=never --style=full'" "$ROOT/.bashrc" || fail 'missing bat fallback alias'
+
+BAT_TEST_DIR="$TMPDIR/bat-test"
+mkdir -p "$BAT_TEST_DIR"
+cat >"$BAT_TEST_DIR/batcat" <<'EOF'
+#!/bin/sh
+printf 'args:%s\n' "$*"
+cat
+EOF
+chmod +x "$BAT_TEST_DIR/batcat"
+bat_output=$(PATH="$BAT_TEST_DIR:/usr/bin:/bin" HOME="$TMPDIR" bash --noprofile --rcfile "$ROOT/.bashrc" -ic 'printf payload | cat' 2>/dev/null)
+[[ $bat_output == $'args:--paging=never --style=full\npayload' ]] || fail "interactive cat did not invoke batcat directly: $bat_output"
+
+BAT_FALLBACK_DIR="$TMPDIR/bat-fallback-test"
+mkdir -p "$BAT_FALLBACK_DIR"
+cat >"$BAT_FALLBACK_DIR/bat" <<'EOF'
+#!/bin/sh
+printf 'args:%s\n' "$*"
+/bin/cat
+EOF
+chmod +x "$BAT_FALLBACK_DIR/bat"
+bat_fallback_output=$(PATH="$BAT_FALLBACK_DIR" HOME="$TMPDIR" /bin/bash --noprofile --rcfile "$ROOT/.bashrc" -ic 'printf payload | cat' 2>/dev/null)
+[[ $bat_fallback_output == $'args:--paging=never --style=full\npayload' ]] || fail "cat alias did not invoke bat fallback correctly: $bat_fallback_output"
+
+REAL_BAT=$(command -v batcat || command -v bat || true)
+[[ -n $REAL_BAT ]] || fail 'batcat/bat is required for the rendering contract'
+command -v script >/dev/null 2>&1 || fail 'script is required for the rendering contract'
+RENDER_HOME="$TMPDIR/render-home"
+mkdir -p "$RENDER_HOME/bin"
+ln -s "$REAL_BAT" "$RENDER_HOME/bin/$(basename "$REAL_BAT")"
+printf '%s\n' 'PING 192.168.88.1 (192.168.88.1)' '64 bytes from 192.168.88.1' >"$RENDER_HOME/ping.txt"
+render_output=$(TERM=xterm-256color PATH="$RENDER_HOME/bin:/usr/bin:/bin" HOME="$RENDER_HOME" \
+  script -qec "bash --noprofile --rcfile '$ROOT/.bashrc' -ic 'cat \"$RENDER_HOME/ping.txt\"'" /dev/null 2>/dev/null)
+[[ $render_output == *'ping.txt'* ]] || fail 'interactive cat rendering lacks the bat file header'
+[[ $render_output == *'1'*'PING 192.168.88.1'* ]] || fail 'interactive cat rendering lacks bat line numbers/grid'
+[[ $render_output == *$'\033['* ]] || fail 'interactive cat rendering lacks terminal color escapes'
+
+noninteractive_output=$(PATH="$BAT_TEST_DIR:/usr/bin:/bin" HOME="$TMPDIR" bash --noprofile -c '. "$1"; printf payload | cat' bash "$ROOT/.bashrc" 2>/dev/null)
+[[ $noninteractive_output == payload ]] || fail "non-interactive cat behavior changed: $noninteractive_output"
+bypass_output=$(PATH="$BAT_TEST_DIR:/usr/bin:/bin" HOME="$TMPDIR" bash --noprofile --rcfile "$ROOT/.bashrc" -ic 'printf payload | command cat' 2>/dev/null)
+[[ $bypass_output == payload ]] || fail "command cat did not bypass the alias: $bypass_output"
+
+LOGIN_HOME="$TMPDIR/login-home"
+mkdir -p "$LOGIN_HOME"
+printf '# existing profile\n' >"$LOGIN_HOME/.profile"
+ln -s "$ROOT/.bashrc" "$LOGIN_HOME/.bashrc"
+(
+  export HOME="$LOGIN_HOME" MYBASH_SETUP_LIB_ONLY=1 PATH="$BAT_TEST_DIR:/usr/bin:/bin"
+  # shellcheck source=/dev/null
+  . "$ROOT/setup.sh"
+  # shellcheck disable=SC2034 # Consumed by the sourced setup function.
+  OS_NAME=Linux
+  ensure_login_profile_sources_bashrc
+  ensure_login_profile_sources_bashrc
+)
+# shellcheck disable=SC2016 # Match the literal profile command.
+grep -Fq '. "$HOME/.bashrc"' "$LOGIN_HOME/.profile" || fail 'Linux login profile does not source .bashrc'
+# shellcheck disable=SC2016 # Match the literal profile command.
+[[ $(grep -Fc '. "$HOME/.bashrc"' "$LOGIN_HOME/.profile") -eq 1 ]] || fail 'login profile sources .bashrc more than once'
+/bin/sh -c '. "$1"' sh "$LOGIN_HOME/.profile" >/dev/null 2>&1 || fail 'generated .profile is unsafe for non-Bash shells'
+
+PROFILE_HOME="$TMPDIR/bash-profile-home"
+mkdir -p "$PROFILE_HOME"
+# shellcheck disable=SC2016 # Write the literal ${HOME} profile form.
+printf '%s\n' '. "${HOME}/.bashrc"' >"$PROFILE_HOME/.bash_profile"
+(
+  export HOME="$PROFILE_HOME" MYBASH_SETUP_LIB_ONLY=1
+  # shellcheck source=/dev/null
+  . "$ROOT/setup.sh"
+  # shellcheck disable=SC2034 # Consumed by the sourced setup function.
+  OS_NAME=Linux
+  ensure_login_profile_sources_bashrc
+)
+[[ $(grep -c '\.bashrc' "$PROFILE_HOME/.bash_profile") -eq 1 ]] || fail 'existing bash profile received a duplicate .bashrc source block'
+[[ ! -e $PROFILE_HOME/.profile ]] || fail 'setup ignored existing .bash_profile precedence'
+
+VERIFY_HOME="$TMPDIR/verify-home"
+mkdir -p "$VERIFY_HOME/bin"
+cat >"$VERIFY_HOME/bin/batcat" <<'EOF'
+#!/bin/sh
+exit 0
+EOF
+cat >"$VERIFY_HOME/bin/bash" <<'EOF'
+#!/bin/sh
+printf '%s\n' "$*" >"$HOME/bash-args"
+printf "%s\n" "alias cat='batcat --paging=never --style=full'" >&3
+EOF
+chmod +x "$VERIFY_HOME/bin/batcat" "$VERIFY_HOME/bin/bash"
+(
+  export HOME="$VERIFY_HOME" MYBASH_SETUP_LIB_ONLY=1 PATH="$VERIFY_HOME/bin:/usr/bin:/bin"
+  # shellcheck source=/dev/null
+  . "$ROOT/setup.sh"
+  verify_interactive_cat_alias >/dev/null
+)
+grep -Fq -- '--login -ic alias cat >&3' "$VERIFY_HOME/bash-args" || fail 'alias verification did not use a login shell'
+
+printf 'Shell integration tests passed.\n'
\ No newline at end of file