diff --git a/.github/workflows/test-install.yml b/.github/workflows/test-install.yml
new file mode 100644
index 00000000..416adef6
--- /dev/null
+++ b/.github/workflows/test-install.yml
@@ -0,0 +1,51 @@
+name: Test Install Script
+
+on:
+  pull_request:
+    paths:
+      - 'install.sh'
+      - 'e2e/install/**'
+      - '.github/workflows/test-install.yml'
+  push:
+    branches: [main]
+    paths:
+      - 'install.sh'
+      - 'e2e/install/**'
+      - '.github/workflows/test-install.yml'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  test-install:
+    name: install.sh (${{ matrix.shell }})
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - shell: sh
+            test: e2e/install/sh_test.sh
+            run: sh e2e/install/sh_test.sh
+          - shell: bash
+            test: e2e/install/bash_test.sh
+            run: bash e2e/install/bash_test.sh
+          - shell: zsh
+            test: e2e/install/zsh_test.sh
+            run: zsh e2e/install/zsh_test.sh
+            install: zsh
+          - shell: fish
+            test: e2e/install/fish_test.fish
+            run: fish e2e/install/fish_test.fish
+            install: fish
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install ${{ matrix.shell }}
+        if: matrix.install
+        run: sudo apt-get update && sudo apt-get install -y ${{ matrix.install }}
+
+      - name: Run tests (${{ matrix.shell }})
+        run: ${{ matrix.run }}
diff --git a/e2e/install/bash_test.sh b/e2e/install/bash_test.sh
new file mode 100755
index 00000000..2b4db1ca
--- /dev/null
+++ b/e2e/install/bash_test.sh
@@ -0,0 +1,80 @@
+#!/bin/bash
+# SPDX-FileCopyrightText: Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+#
+# Bash e2e tests for install.sh.
+#
+# Downloads the latest release for real and validates:
+#   - Binary is installed to the correct directory
+#   - Binary is executable and runs
+#   - PATH guidance shows the correct export command for bash
+#
+set -euo pipefail
+
+. "$(dirname "$0")/helpers.sh"
+
+# ---------------------------------------------------------------------------
+# Tests
+# ---------------------------------------------------------------------------
+
+test_binary_installed() {
+  printf 'TEST: binary exists in install directory\n'
+
+  if [ -f "$INSTALL_DIR/openshell" ]; then
+    pass "openshell binary exists at $INSTALL_DIR/openshell"
+  else
+    fail "openshell binary exists" "not found at $INSTALL_DIR/openshell"
+  fi
+}
+
+test_binary_executable() {
+  printf 'TEST: binary is executable\n'
+
+  if [ -x "$INSTALL_DIR/openshell" ]; then
+    pass "openshell binary is executable"
+  else
+    fail "openshell binary is executable" "$INSTALL_DIR/openshell is not executable"
+  fi
+}
+
+test_binary_runs() {
+  printf 'TEST: binary runs successfully\n'
+
+  if _version="$("$INSTALL_DIR/openshell" --version 2>/dev/null)"; then
+    pass "openshell --version succeeds: $_version"
+  else
+    fail "openshell --version succeeds" "exit code: $?"
+  fi
+}
+
+test_guidance_shows_export_path() {
+  printf 'TEST: guidance shows export PATH for bash users\n'
+
+  assert_output_contains "$INSTALL_OUTPUT" 'export PATH="' "shows export PATH command"
+  assert_output_not_contains "$INSTALL_OUTPUT" "fish_add_path" "does not show fish command"
+}
+
+test_guidance_mentions_not_on_path() {
+  printf 'TEST: guidance mentions install dir is not on PATH\n'
+
+  assert_output_contains "$INSTALL_OUTPUT" "is not on your PATH" "mentions PATH issue"
+  assert_output_contains "$INSTALL_OUTPUT" "$INSTALL_DIR" "includes install dir in guidance"
+}
+
+# ---------------------------------------------------------------------------
+# Runner
+# ---------------------------------------------------------------------------
+
+printf '=== install.sh e2e tests: bash ===\n\n'
+
+printf 'Installing openshell...\n'
+SHELL="/bin/bash" run_install
+printf 'Done.\n\n'
+
+test_binary_installed;              echo ""
+test_binary_executable;             echo ""
+test_binary_runs;                   echo ""
+test_guidance_shows_export_path;    echo ""
+test_guidance_mentions_not_on_path
+
+print_summary
diff --git a/e2e/install/fish_test.fish b/e2e/install/fish_test.fish
new file mode 100755
index 00000000..10176071
--- /dev/null
+++ b/e2e/install/fish_test.fish
@@ -0,0 +1,152 @@
+#!/usr/bin/env fish
+# SPDX-FileCopyrightText: Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+#
+# Fish e2e tests for install.sh.
+#
+# Downloads the latest release for real and validates:
+#   - Binary is installed to the correct directory
+#   - Binary is executable and runs
+#   - PATH guidance shows fish_add_path (not export PATH)
+
+set -g PASS 0
+set -g FAIL 0
+
+# Resolve paths relative to this script
+set -g SCRIPT_DIR (builtin cd (dirname (status filename)) && pwd)
+set -g REPO_ROOT (builtin cd "$SCRIPT_DIR/../.." && pwd)
+set -g INSTALL_SCRIPT "$REPO_ROOT/install.sh"
+
+# Set by run_install
+set -g INSTALL_DIR ""
+set -g INSTALL_OUTPUT ""
+
+# ---------------------------------------------------------------------------
+# Helpers
+# ---------------------------------------------------------------------------
+
+function pass
+    set -g PASS (math $PASS + 1)
+    printf '  PASS: %s\n' $argv[1]
+end
+
+function fail
+    set -g FAIL (math $FAIL + 1)
+    printf '  FAIL: %s\n' $argv[1] >&2
+    if test (count $argv) -gt 1
+        printf '        %s\n' $argv[2] >&2
+    end
+end
+
+function assert_output_contains
+    set -l output $argv[1]
+    set -l pattern $argv[2]
+    set -l label $argv[3]
+
+    if string match -q -- "*$pattern*" "$output"
+        pass "$label"
+    else
+        fail "$label" "expected '$pattern' in output"
+    end
+end
+
+function assert_output_not_contains
+    set -l output $argv[1]
+    set -l pattern $argv[2]
+    set -l label $argv[3]
+
+    if string match -q -- "*$pattern*" "$output"
+        fail "$label" "unexpected '$pattern' found in output"
+    else
+        pass "$label"
+    end
+end
+
+function run_install
+    set -g INSTALL_DIR (mktemp -d)/bin
+
+    set -g INSTALL_OUTPUT (OPENSHELL_INSTALL_DIR="$INSTALL_DIR" \
+        SHELL="/usr/bin/fish" \
+        PATH="/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin" \
+        sh "$INSTALL_SCRIPT" 2>&1)
+
+    if test $status -ne 0
+        printf 'install.sh failed:\n%s\n' "$INSTALL_OUTPUT" >&2
+        return 1
+    end
+end
+
+# ---------------------------------------------------------------------------
+# Tests
+# ---------------------------------------------------------------------------
+
+function test_binary_installed
+    printf 'TEST: binary exists in install directory\n'
+
+    if test -f "$INSTALL_DIR/openshell"
+        pass "openshell binary exists at $INSTALL_DIR/openshell"
+    else
+        fail "openshell binary exists" "not found at $INSTALL_DIR/openshell"
+    end
+end
+
+function test_binary_executable
+    printf 'TEST: binary is executable\n'
+
+    if test -x "$INSTALL_DIR/openshell"
+        pass "openshell binary is executable"
+    else
+        fail "openshell binary is executable" "$INSTALL_DIR/openshell is not executable"
+    end
+end
+
+function test_binary_runs
+    printf 'TEST: binary runs successfully\n'
+
+    set -l version_output ("$INSTALL_DIR/openshell" --version 2>/dev/null)
+    if test $status -eq 0
+        pass "openshell --version succeeds: $version_output"
+    else
+        fail "openshell --version succeeds" "exit code: $status"
+    end
+end
+
+function test_guidance_shows_fish_add_path
+    printf 'TEST: guidance shows fish_add_path for fish users\n'
+
+    assert_output_contains "$INSTALL_OUTPUT" "fish_add_path" "shows fish_add_path command"
+    assert_output_not_contains "$INSTALL_OUTPUT" 'export PATH="' "does not show POSIX export"
+end
+
+function test_guidance_mentions_not_on_path
+    printf 'TEST: guidance mentions install dir is not on PATH\n'
+
+    assert_output_contains "$INSTALL_OUTPUT" "is not on your PATH" "mentions PATH issue"
+    assert_output_contains "$INSTALL_OUTPUT" "$INSTALL_DIR" "includes install dir in guidance"
+end
+
+# ---------------------------------------------------------------------------
+# Runner
+# ---------------------------------------------------------------------------
+
+printf '=== install.sh e2e tests: fish ===\n\n'
+
+printf 'Installing openshell...\n'
+run_install
+printf 'Done.\n\n'
+
+test_binary_installed
+echo ""
+test_binary_executable
+echo ""
+test_binary_runs
+echo ""
+test_guidance_shows_fish_add_path
+echo ""
+test_guidance_mentions_not_on_path
+
+printf '\n=== Results: %d passed, %d failed ===\n' $PASS $FAIL
+
+if test $FAIL -gt 0
+    exit 1
+end
diff --git a/e2e/install/helpers.sh b/e2e/install/helpers.sh
new file mode 100644
index 00000000..ff5f6637
--- /dev/null
+++ b/e2e/install/helpers.sh
@@ -0,0 +1,100 @@
+#!/bin/sh
+# SPDX-FileCopyrightText: Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+#
+# Shared test helpers for install.sh e2e tests.
+# Sourced by each per-shell test file (except fish, which has its own helpers).
+#
+# Provides:
+#   - pass / fail / print_summary
+#   - assert_output_contains / assert_output_not_contains
+#   - run_install          (runs the real install.sh to a temp dir, captures output)
+#   - REPO_ROOT / INSTALL_SCRIPT paths
+#   - INSTALL_DIR / INSTALL_OUTPUT (set after run_install)
+
+HELPERS_DIR="$(cd "$(dirname "$0")" && pwd)"
+REPO_ROOT="$(cd "$HELPERS_DIR/../.." && pwd)"
+INSTALL_SCRIPT="$REPO_ROOT/install.sh"
+
+_PASS=0
+_FAIL=0
+
+# Set by run_install
+INSTALL_DIR=""
+INSTALL_OUTPUT=""
+
+# ---------------------------------------------------------------------------
+# Assertions
+# ---------------------------------------------------------------------------
+
+pass() {
+  _PASS=$((_PASS + 1))
+  printf '  PASS: %s\n' "$1"
+}
+
+fail() {
+  _FAIL=$((_FAIL + 1))
+  printf '  FAIL: %s\n' "$1" >&2
+  if [ -n "${2:-}" ]; then
+    printf '        %s\n' "$2" >&2
+  fi
+}
+
+assert_output_contains() {
+  _aoc_output="$1"
+  _aoc_pattern="$2"
+  _aoc_label="$3"
+
+  if printf '%s' "$_aoc_output" | grep -qF "$_aoc_pattern"; then
+    pass "$_aoc_label"
+  else
+    fail "$_aoc_label" "expected '$_aoc_pattern' in output"
+  fi
+}
+
+assert_output_not_contains() {
+  _aonc_output="$1"
+  _aonc_pattern="$2"
+  _aonc_label="$3"
+
+  if printf '%s' "$_aonc_output" | grep -qF "$_aonc_pattern"; then
+    fail "$_aonc_label" "unexpected '$_aonc_pattern' found in output"
+  else
+    pass "$_aonc_label"
+  fi
+}
+
+# ---------------------------------------------------------------------------
+# Install runner
+# ---------------------------------------------------------------------------
+
+# Run the real install.sh, installing to a temp directory with the install
+# dir removed from PATH so we always get PATH guidance output.
+#
+# Sets INSTALL_DIR and INSTALL_OUTPUT for subsequent assertions.
+# The SHELL variable is passed through so tests can control which shell
+# guidance is shown.
+#
+# Usage:
+#   SHELL="/bin/bash" run_install
+run_install() {
+  INSTALL_DIR="$(mktemp -d)/bin"
+
+  # Remove the install dir from PATH (it won't be there, but be explicit).
+  # Keep a minimal PATH so curl/tar/install are available.
+  INSTALL_OUTPUT="$(OPENSHELL_INSTALL_DIR="$INSTALL_DIR" \
+    PATH="/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin" \
+    sh "$INSTALL_SCRIPT" 2>&1)" || {
+    printf 'install.sh failed:\n%s\n' "$INSTALL_OUTPUT" >&2
+    return 1
+  }
+}
+
+# ---------------------------------------------------------------------------
+# Summary
+# ---------------------------------------------------------------------------
+
+print_summary() {
+  printf '\n=== Results: %d passed, %d failed ===\n' "$_PASS" "$_FAIL"
+  [ "$_FAIL" -eq 0 ]
+}
diff --git a/e2e/install/sh_test.sh b/e2e/install/sh_test.sh
new file mode 100755
index 00000000..320c00ef
--- /dev/null
+++ b/e2e/install/sh_test.sh
@@ -0,0 +1,105 @@
+#!/bin/sh
+# SPDX-FileCopyrightText: Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+#
+# POSIX sh e2e tests for install.sh.
+#
+# Downloads the latest release for real and validates:
+#   - Binary is installed to the correct directory
+#   - Binary is executable and runs
+#   - PATH guidance shows the correct export command for sh
+#   - No rc files or env scripts are created
+#
+set -eu
+
+. "$(dirname "$0")/helpers.sh"
+
+# ---------------------------------------------------------------------------
+# Tests
+# ---------------------------------------------------------------------------
+
+test_binary_installed() {
+  printf 'TEST: binary exists in install directory\n'
+
+  if [ -f "$INSTALL_DIR/openshell" ]; then
+    pass "openshell binary exists at $INSTALL_DIR/openshell"
+  else
+    fail "openshell binary exists" "not found at $INSTALL_DIR/openshell"
+  fi
+}
+
+test_binary_executable() {
+  printf 'TEST: binary is executable\n'
+
+  if [ -x "$INSTALL_DIR/openshell" ]; then
+    pass "openshell binary is executable"
+  else
+    fail "openshell binary is executable" "$INSTALL_DIR/openshell is not executable"
+  fi
+}
+
+test_binary_runs() {
+  printf 'TEST: binary runs successfully\n'
+
+  if _version="$("$INSTALL_DIR/openshell" --version 2>/dev/null)"; then
+    pass "openshell --version succeeds: $_version"
+  else
+    fail "openshell --version succeeds" "exit code: $?"
+  fi
+}
+
+test_guidance_shows_export_path() {
+  printf 'TEST: guidance shows export PATH for sh users\n'
+
+  assert_output_contains "$INSTALL_OUTPUT" 'export PATH="' "shows export PATH command"
+  assert_output_not_contains "$INSTALL_OUTPUT" "fish_add_path" "does not show fish command"
+}
+
+test_guidance_mentions_not_on_path() {
+  printf 'TEST: guidance mentions install dir is not on PATH\n'
+
+  assert_output_contains "$INSTALL_OUTPUT" "is not on your PATH" "mentions PATH issue"
+  assert_output_contains "$INSTALL_OUTPUT" "$INSTALL_DIR" "includes install dir in guidance"
+}
+
+test_guidance_mentions_restart() {
+  printf 'TEST: guidance tells user to restart shell\n'
+
+  assert_output_contains "$INSTALL_OUTPUT" "restart your shell" "mentions shell restart"
+}
+
+test_no_env_scripts_created() {
+  printf 'TEST: no env scripts are created in install dir\n'
+
+  if [ -f "$INSTALL_DIR/env" ]; then
+    fail "no env script created" "found $INSTALL_DIR/env"
+  else
+    pass "no env script created"
+  fi
+
+  if [ -f "$INSTALL_DIR/env.fish" ]; then
+    fail "no env.fish script created" "found $INSTALL_DIR/env.fish"
+  else
+    pass "no env.fish script created"
+  fi
+}
+
+# ---------------------------------------------------------------------------
+# Runner
+# ---------------------------------------------------------------------------
+
+printf '=== install.sh e2e tests: sh ===\n\n'
+
+printf 'Installing openshell...\n'
+SHELL="/bin/sh" run_install
+printf 'Done.\n\n'
+
+test_binary_installed;            echo ""
+test_binary_executable;           echo ""
+test_binary_runs;                 echo ""
+test_guidance_shows_export_path;  echo ""
+test_guidance_mentions_not_on_path; echo ""
+test_guidance_mentions_restart;   echo ""
+test_no_env_scripts_created
+
+print_summary
diff --git a/e2e/install/zsh_test.sh b/e2e/install/zsh_test.sh
new file mode 100755
index 00000000..621d35f8
--- /dev/null
+++ b/e2e/install/zsh_test.sh
@@ -0,0 +1,80 @@
+#!/bin/zsh
+# SPDX-FileCopyrightText: Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+#
+# Zsh e2e tests for install.sh.
+#
+# Downloads the latest release for real and validates:
+#   - Binary is installed to the correct directory
+#   - Binary is executable and runs
+#   - PATH guidance shows the correct export command for zsh
+#
+set -eu
+
+. "$(dirname "$0")/helpers.sh"
+
+# ---------------------------------------------------------------------------
+# Tests
+# ---------------------------------------------------------------------------
+
+test_binary_installed() {
+  printf 'TEST: binary exists in install directory\n'
+
+  if [ -f "$INSTALL_DIR/openshell" ]; then
+    pass "openshell binary exists at $INSTALL_DIR/openshell"
+  else
+    fail "openshell binary exists" "not found at $INSTALL_DIR/openshell"
+  fi
+}
+
+test_binary_executable() {
+  printf 'TEST: binary is executable\n'
+
+  if [ -x "$INSTALL_DIR/openshell" ]; then
+    pass "openshell binary is executable"
+  else
+    fail "openshell binary is executable" "$INSTALL_DIR/openshell is not executable"
+  fi
+}
+
+test_binary_runs() {
+  printf 'TEST: binary runs successfully\n'
+
+  if _version="$("$INSTALL_DIR/openshell" --version 2>/dev/null)"; then
+    pass "openshell --version succeeds: $_version"
+  else
+    fail "openshell --version succeeds" "exit code: $?"
+  fi
+}
+
+test_guidance_shows_export_path() {
+  printf 'TEST: guidance shows export PATH for zsh users\n'
+
+  assert_output_contains "$INSTALL_OUTPUT" 'export PATH="' "shows export PATH command"
+  assert_output_not_contains "$INSTALL_OUTPUT" "fish_add_path" "does not show fish command"
+}
+
+test_guidance_mentions_not_on_path() {
+  printf 'TEST: guidance mentions install dir is not on PATH\n'
+
+  assert_output_contains "$INSTALL_OUTPUT" "is not on your PATH" "mentions PATH issue"
+  assert_output_contains "$INSTALL_OUTPUT" "$INSTALL_DIR" "includes install dir in guidance"
+}
+
+# ---------------------------------------------------------------------------
+# Runner
+# ---------------------------------------------------------------------------
+
+printf '=== install.sh e2e tests: zsh ===\n\n'
+
+printf 'Installing openshell...\n'
+SHELL="/bin/zsh" run_install
+printf 'Done.\n\n'
+
+test_binary_installed;              echo ""
+test_binary_executable;             echo ""
+test_binary_runs;                   echo ""
+test_guidance_shows_export_path;    echo ""
+test_guidance_mentions_not_on_path
+
+print_summary
diff --git a/install.sh b/install.sh
index d945cde7..faec3bb2 100755
--- a/install.sh
+++ b/install.sh
@@ -14,16 +14,11 @@
 #   OPENSHELL_VERSION     - Release tag to install (default: latest tagged release)
 #   OPENSHELL_INSTALL_DIR - Directory to install into (default: ~/.local/bin)
 #
-# CLI flags:
-#   --help            - Print usage information
-#   --no-modify-path  - Skip PATH modification in shell profiles
-#
 set -eu
 
 APP_NAME="openshell"
 REPO="NVIDIA/OpenShell"
 GITHUB_URL="https://github.com/${REPO}"
-NO_MODIFY_PATH=0
 
 # ---------------------------------------------------------------------------
 # Logging
@@ -55,8 +50,7 @@ USAGE:
     ./install.sh [OPTIONS]
 
 OPTIONS:
-    --no-modify-path    Don't add the install directory to PATH
-    --help              Print this help message
+    --help    Print this help message
 
 ENVIRONMENT VARIABLES:
     OPENSHELL_VERSION       Release tag to install (default: latest tagged release)
@@ -111,8 +105,8 @@ resolve_redirect() {
   if has_cmd curl; then
     curl -fLsS -o /dev/null -w '%{url_effective}' "$_url"
   elif has_cmd wget; then
-    # wget --spider follows redirects and prints the final URL
-    wget --spider -q --max-redirect=10 "$_url" 2>&1 | grep -oP 'Location: \K\S+' | tail -1
+    # wget --spider follows redirects; capture the final Location from stderr
+    wget --spider --max-redirect=10 "$_url" 2>&1 | sed -n 's/^.*Location: \([^ ]*\).*/\1/p' | tail -1
   fi
 }
 
@@ -182,21 +176,21 @@ resolve_version() {
 # ---------------------------------------------------------------------------
 
 verify_checksum() {
-  _archive="$1"
-  _checksums="$2"
-  _filename="$3"
+  _vc_archive="$1"
+  _vc_checksums="$2"
+  _vc_filename="$3"
 
-  _expected="$(grep "$_filename" "$_checksums" | awk '{print $1}')"
+  _vc_expected="$(grep "$_vc_filename" "$_vc_checksums" | awk '{print $1}')"
 
-  if [ -z "$_expected" ]; then
-    warn "no checksum found for $_filename, skipping verification"
+  if [ -z "$_vc_expected" ]; then
+    warn "no checksum found for $_vc_filename, skipping verification"
     return 0
   fi
 
   if has_cmd shasum; then
-    echo "$_expected  $_archive" | shasum -a 256 -c --quiet 2>/dev/null
+    echo "$_vc_expected  $_vc_archive" | shasum -a 256 -c --quiet 2>/dev/null
   elif has_cmd sha256sum; then
-    echo "$_expected  $_archive" | sha256sum -c --quiet 2>/dev/null
+    echo "$_vc_expected  $_vc_archive" | sha256sum -c --quiet 2>/dev/null
   else
     warn "sha256sum/shasum not found, skipping checksum verification"
     return 0
@@ -204,25 +198,14 @@ verify_checksum() {
 }
 
 # ---------------------------------------------------------------------------
-# Install location and PATH management
+# Install location
 # ---------------------------------------------------------------------------
 
-get_home() {
-  if [ -n "${HOME:-}" ]; then
-    echo "$HOME"
-  elif [ -n "${USER:-}" ]; then
-    getent passwd "$USER" | cut -d: -f6
-  else
-    getent passwd "$(id -un)" | cut -d: -f6
-  fi
-}
-
-get_default_install_dir() {
-  if [ -n "${XDG_BIN_HOME:-}" ]; then
-    echo "$XDG_BIN_HOME"
+get_install_dir() {
+  if [ -n "${OPENSHELL_INSTALL_DIR:-}" ]; then
+    echo "$OPENSHELL_INSTALL_DIR"
   else
-    _home="$(get_home)"
-    echo "${_home}/.local/bin"
+    echo "${HOME}/.local/bin"
   fi
 }
 
@@ -235,132 +218,6 @@ is_on_path() {
   esac
 }
 
-# Write a small env script that conditionally prepends the install dir to PATH.
-write_env_script_sh() {
-  _install_dir_expr="$1"
-  _env_script="$2"
-
-  cat <<ENVEOF > "$_env_script"
-#!/bin/sh
-# Add OpenShell to PATH if not already present
-case ":\${PATH}:" in
-  *:"${_install_dir_expr}":*)
-    ;;
-  *)
-    export PATH="${_install_dir_expr}:\$PATH"
-    ;;
-esac
-ENVEOF
-}
-
-write_env_script_fish() {
-  _install_dir_expr="$1"
-  _env_script="$2"
-
-  cat <<ENVEOF > "$_env_script"
-# Add OpenShell to PATH if not already present
-if not contains "${_install_dir_expr}" \$PATH
-    set -gx PATH "${_install_dir_expr}" \$PATH
-end
-ENVEOF
-}
-
-# Add a `. /path/to/env` line to a shell rc file if not already present.
-add_source_line() {
-  _env_script_path="$1"
-  _rcfile="$2"
-  _shell_type="$3"
-
-  if [ "$_shell_type" = "fish" ]; then
-    _line="source \"${_env_script_path}\""
-  else
-    _line=". \"${_env_script_path}\""
-  fi
-
-  # Check if line already exists
-  if [ -f "$_rcfile" ] && grep -qF "$_line" "$_rcfile" 2>/dev/null; then
-    return 0
-  fi
-
-  # Append with a leading newline in case the file doesn't end with one
-  printf '\n%s\n' "$_line" >> "$_rcfile"
-  return 1
-}
-
-# Set up PATH modification in common shell rc files.
-setup_path() {
-  _install_dir="$1"
-  _home="$(get_home)"
-  _env_script="${_install_dir}/env"
-  _fish_env_script="${_install_dir}/env.fish"
-  _needs_source=0
-
-  # Replace $HOME in the expression for late-bound references in rc files
-  if [ -n "${HOME:-}" ]; then
-    # shellcheck disable=SC2016
-    _install_dir_expr='$HOME'"${_install_dir#"$_home"}"
-  else
-    _install_dir_expr="$_install_dir"
-  fi
-
-  # Write the env scripts
-  write_env_script_sh "$_install_dir_expr" "$_env_script"
-  write_env_script_fish "$_install_dir_expr" "$_fish_env_script"
-
-  # POSIX shells: .profile, .bashrc, .bash_profile, .zshrc, .zshenv
-  for _rcfile_rel in .profile .bashrc .bash_profile .zshrc .zshenv; do
-    _rcdir="$_home"
-    # zsh respects ZDOTDIR
-    case "$_rcfile_rel" in
-      .zsh*) _rcdir="${ZDOTDIR:-$_home}" ;;
-    esac
-    _rcfile="${_rcdir}/${_rcfile_rel}"
-    if [ -f "$_rcfile" ]; then
-      if ! add_source_line "$_env_script" "$_rcfile" "sh"; then
-        _needs_source=1
-      fi
-    fi
-  done
-
-  # If none of the above existed, create .profile
-  if [ "$_needs_source" = "0" ]; then
-    _found_any=0
-    for _rcfile_rel in .profile .bashrc .bash_profile .zshrc .zshenv; do
-      if [ -f "${_home}/${_rcfile_rel}" ]; then
-        _found_any=1
-        break
-      fi
-    done
-    if [ "$_found_any" = "0" ]; then
-      if ! add_source_line "$_env_script" "${_home}/.profile" "sh"; then
-        _needs_source=1
-      fi
-    fi
-  fi
-
-  # Fish shell
-  _fish_conf_dir="${_home}/.config/fish/conf.d"
-  if [ -d "${_home}/.config/fish" ]; then
-    mkdir -p "$_fish_conf_dir"
-    add_source_line "$_fish_env_script" "${_fish_conf_dir}/${APP_NAME}.env.fish" "fish" || true
-  fi
-
-  # GitHub Actions: write to GITHUB_PATH for CI environments
-  if [ -n "${GITHUB_PATH:-}" ]; then
-    echo "$_install_dir" >> "$GITHUB_PATH"
-  fi
-
-  if [ "$_needs_source" = "1" ] || ! is_on_path "$_install_dir"; then
-    echo ""
-    info "to add ${APP_NAME} to your PATH, restart your shell or run:"
-    info ""
-    info "    source \"${_env_script}\"    (sh, bash, zsh)"
-    if [ -d "${_home}/.config/fish" ]; then
-      info "    source \"${_fish_env_script}\"    (fish)"
-    fi
-  fi
-}
-
 # ---------------------------------------------------------------------------
 # Main
 # ---------------------------------------------------------------------------
@@ -373,9 +230,6 @@ main() {
         usage
         exit 0
         ;;
-      --no-modify-path)
-        NO_MODIFY_PATH=1
-        ;;
       *)
         error "unknown option: $arg"
         ;;
@@ -389,15 +243,7 @@ main() {
   _filename="${APP_NAME}-${_target}.tar.gz"
   _download_url="${GITHUB_URL}/releases/download/${_version}/${_filename}"
   _checksums_url="${GITHUB_URL}/releases/download/${_version}/${APP_NAME}-checksums-sha256.txt"
-
-  # Determine install directory
-  _using_default_dir=0
-  if [ -n "${OPENSHELL_INSTALL_DIR:-}" ]; then
-    _install_dir="$OPENSHELL_INSTALL_DIR"
-  else
-    _install_dir="$(get_default_install_dir)"
-    _using_default_dir=1
-  fi
+  _install_dir="$(get_install_dir)"
 
   info "downloading ${APP_NAME} ${_version} (${_target})..."
 
@@ -436,11 +282,27 @@ main() {
   _installed_version="$("${_install_dir}/${APP_NAME}" --version 2>/dev/null || echo "${_version}")"
   info "installed ${APP_NAME} ${_installed_version} to ${_install_dir}/${APP_NAME}"
 
-  # Set up PATH for default install location
-  if [ "$_using_default_dir" = "1" ] && [ "$NO_MODIFY_PATH" = "0" ]; then
-    if ! is_on_path "$_install_dir"; then
-      setup_path "$_install_dir"
-    fi
+  # If the install directory isn't on PATH, print instructions
+  if ! is_on_path "$_install_dir"; then
+    echo ""
+    info "${_install_dir} is not on your PATH."
+    info ""
+    info "Add it by appending the following to your shell configuration file"
+    info "(e.g. ~/.bashrc, ~/.zshrc, or ~/.config/fish/config.fish):"
+    info ""
+
+    _current_shell="$(basename "${SHELL:-sh}" 2>/dev/null || echo "sh")"
+    case "$_current_shell" in
+      fish)
+        info "    fish_add_path ${_install_dir}"
+        ;;
+      *)
+        info "    export PATH=\"${_install_dir}:\$PATH\""
+        ;;
+    esac
+
+    info ""
+    info "Then restart your shell or run the command above in your current session."
   fi
 }