diff --git a/.github/workflows/test-compat.yml b/.github/workflows/test-compat.yml
index f9b3b47..baf0207 100644
--- a/.github/workflows/test-compat.yml
+++ b/.github/workflows/test-compat.yml
@@ -165,3 +165,6 @@ jobs:
 
       - name: signal-handling
         run: ./tests/sigwinch.sh
+
+      - name: nginx binary location
+        run: ./tests/nginx-bin-search.sh
diff --git a/README.md b/README.md
index 3a31789..2c566b1 100644
--- a/README.md
+++ b/README.md
@@ -62,6 +62,7 @@ CLI metadata, error messages, and nginx.conf, I recommend against using `rusty-c
         - [x] custom runner arg parsing and execution
         - [x] lua `arg` global generation
         - [x] nginx.conf generation
+        - [x] nginx binary filesystem location search
 - [ ] automated binary releases
     - [x] x86_64-unknown-linux-gnu
     - [x] x86_64-unknown-linux-musl
diff --git a/src/nginx.rs b/src/nginx.rs
index cdaf704..64be579 100644
--- a/src/nginx.rs
+++ b/src/nginx.rs
@@ -401,14 +401,15 @@ pub(crate) fn find_nginx_bin(nginx: Option<String>) -> PathBuf {
         return PathBuf::from(path);
     }
 
-    let parent = get_exe().and_then(get_parent).unwrap_or(PathBuf::from("/"));
+    let bin_dir = get_exe().and_then(get_parent).unwrap_or(PathBuf::from("/"));
 
-    let nginx = parent.join("nginx/sbin/nginx");
+    // compatibility: resty-cli uses '..' and does not normalize this path
+    let nginx = bin_dir.join("../nginx/sbin/nginx");
     if nginx.is_file() {
         return nginx;
     }
 
-    let nginx = parent.join("nginx");
+    let nginx = bin_dir.join("nginx");
     if nginx.is_file() {
         return nginx;
     }
diff --git a/tests/nginx-bin-search.sh b/tests/nginx-bin-search.sh
new file mode 100755
index 0000000..211a1cc
--- /dev/null
+++ b/tests/nginx-bin-search.sh
@@ -0,0 +1,360 @@
+#!/usr/bin/env bash
+
+set -eu
+readonly RUSTY=./target/debug/rusty-cli
+readonly RESTY=./resty-cli/bin/resty
+
+readonly PATH_SAVE=$PATH
+
+declare -a FAILED=()
+declare -i RAN=0
+
+if [[ ${CI:-} == "true" ]]; then
+    readonly CI=1
+
+    log-err() {
+        echo "::error::$1"
+    }
+
+    log-group() {
+        if [[ -n ${1:-} ]]; then
+            echo "::group::$1"
+
+        else
+            echo "::endgroup::"
+        fi
+    }
+
+else
+    readonly CI=0
+
+    log-err() {
+        echo "$1"
+    }
+
+    log-group() {
+        if [[ -n ${1:-} ]]; then
+            echo "$1"
+        else
+            echo "-----------------------"
+        fi
+    }
+
+fi
+
+expect() {
+    local -r exp=$1
+    shift
+
+    local -r bin=$1
+    shift
+
+    local tmp; tmp=$(mktemp -d)
+
+    "$bin" "$@" \
+        >"$tmp/stdout" \
+        2>"$tmp/stderr"
+
+    local ec=$?
+
+    local stdout; stdout=$(< "$tmp/stdout")
+    local stderr; stderr=$(< "$tmp/stderr")
+
+    rm -rf "$tmp"
+
+    if [[ "$stdout" == "$exp" ]]; then
+        echo "OK ($bin)"
+        echo "  ARG       => $*"
+        echo "  EXPECTED  => '$exp'"
+        echo "  RESULT    => '$stdout'"
+        echo "  STDERR    => '$stderr'"
+        echo "  EXIT      => $ec"
+    else
+        echo "FAILURE ($bin)"
+        echo "  ARG       => $*"
+        echo "  EXPECTED  => '$exp'"
+        echo "  RESULT    => '$stdout'"
+        echo "  STDERR    => '$stderr'"
+        echo "  EXIT      => $ec"
+        return 1
+    fi
+}
+
+expect-PATH() {
+    local -r name=$1
+    local -r expect=$2
+
+    expect "$expect" type -p -f -P "$name" || return 1
+}
+
+
+expect-nginx() {
+    local -r nginx=$1
+    local -r resty=$2
+    shift 2
+
+    expect "$nginx" "$resty" -e 'return' "$@"
+}
+
+copy-binary() {
+    local src=$1
+    local dst=$2
+
+    local parent; parent=$(dirname "$dst")
+    mkdir -p "$parent"
+
+    if [[ -e "$dst" ]]; then
+        echo "$dst already exists"
+        return 1
+    fi
+
+    cp --no-clobber --preserve=all "$src" "$dst"
+}
+
+setup-nginx() {
+    local -r dst=$1
+    copy-binary ./tests/print-argv0 "$dst"
+}
+
+symlink() {
+    local -r target=$1
+    local -r link_name=$2
+
+    local parent=; parent=$(dirname "$link_name")
+    mkdir -p "$parent"
+
+    ln -sf "$target" "$link_name"
+}
+
+run-test() {
+    local -r name=$1
+    local -r func=$2
+
+    local tmp; tmp=$(mktemp -d)
+    log-group "$name"
+
+    export PATH=$PATH_SAVE
+
+    local test_bin=$RESTY
+    echo "test bin => $test_bin"
+    if ! "$func" "$tmp" "$test_bin"; then
+        FAILED+=("$name ($test_bin)")
+    fi
+
+    export PATH=$PATH_SAVE
+
+    rm -rf "$tmp"
+    tmp=$(mktemp -d)
+
+    test_bin=$RUSTY
+    echo "test bin => $test_bin"
+    if ! "$func" "$tmp" "$test_bin"; then
+        FAILED+=("$name ($test_bin)")
+    fi
+
+    export PATH=$PATH_SAVE
+
+    log-group
+
+    rm -rf "$tmp"
+
+    (( RAN++ )) || true
+
+    return 0
+}
+
+test::explicit-nginx() {
+    local -r tmp=$1
+    local -r test_bin=$2
+
+    local -r nginx="$tmp/bin/whatever/nginx"
+    setup-nginx "$nginx"
+
+    expect-nginx "$nginx" "$test_bin" --nginx "$nginx"
+}
+
+test::resty-nginx-sbin() {
+    local -r tmp=$1
+    local -r test_bin=$2
+
+    local -r nginx="$tmp/openresty/bin/../nginx/sbin/nginx"
+
+    setup-nginx "$nginx"
+    local -r resty="$tmp/openresty/bin/resty"
+    copy-binary "$test_bin" "$resty"
+    expect-nginx "$nginx" "$resty"
+}
+
+test::resty-nginx-sbin-via-symlink() {
+    local -r tmp=$1
+    local -r test_bin=$2
+
+    local -r nginx="$tmp/openresty/bin/../nginx/sbin/nginx"
+    setup-nginx "$nginx"
+
+    local resty="$tmp/openresty/bin/resty"
+    copy-binary "$test_bin" "$resty"
+
+    local resty_link="$tmp/symlinks-resty/resty"
+    symlink "$resty" "$resty_link"
+
+    expect-nginx "$nginx" "$resty_link"
+}
+
+test::resty-nginx-sbin-via-PATH-symlink() {
+    local -r tmp=$1
+    local -r test_bin=$2
+
+    local -r nginx="$tmp/openresty/bin/../nginx/sbin/nginx"
+    setup-nginx "$nginx"
+
+    local resty=$tmp/openresty/bin/resty
+    copy-binary "$test_bin" "$resty"
+
+    local resty_link="$tmp/symlinks/resty"
+    symlink "$resty" "$resty_link"
+
+    expect-nginx "$nginx" "$resty_link"
+
+    export PATH="$tmp/symlinks:$PATH"
+    expect-PATH resty "$tmp/symlinks/resty"
+    expect-nginx "$nginx" "resty"
+}
+
+
+test::resty-nginx-sbin-precedence-vs-sibling() {
+    local -r tmp=$1
+    local -r test_bin=$2
+
+    local -r sibling="$tmp/openresty/bin/nginx"
+    setup-nginx "$sibling"
+
+    local resty=$tmp/openresty/bin/resty
+    copy-binary "$test_bin" "$resty"
+
+    # sibling
+    expect-nginx "$sibling" "$resty"
+
+    # ../nginx/sbin/nginx
+    local -r nginx="$tmp/openresty/bin/../nginx/sbin/nginx"
+    setup-nginx "$nginx"
+
+    expect-nginx "$nginx" "$resty"
+}
+
+test::resty-nginx-sbin-precedence-vs-PATH() {
+    local -r tmp=$1
+    local -r test_bin=$2
+
+    local -r path="$tmp/path-search"
+    local -r in_path="$path/nginx"
+    setup-nginx "$in_path"
+
+    export PATH=${path}:$PATH
+    expect-PATH nginx "$in_path"
+
+    local resty=$tmp/openresty/bin/resty
+    copy-binary "$test_bin" "$resty"
+
+    # PATH
+    expect-nginx "$in_path" "$resty"
+
+    # ../nginx/sbin/nginx
+    local -r nginx="$tmp/openresty/bin/../nginx/sbin/nginx"
+    setup-nginx "$nginx"
+
+    expect-PATH nginx "$in_path"
+
+    expect-nginx "$nginx" "$resty"
+}
+
+test::sibling-nginx() {
+    local -r tmp=$1
+    local -r test_bin=$2
+
+    local -r nginx="$tmp/openresty/bin/nginx"
+    setup-nginx "$nginx"
+
+    local resty=$tmp/openresty/bin/resty
+    copy-binary "$test_bin" "$resty"
+
+    expect-nginx "$nginx" "$resty"
+}
+
+test::sibling-nginx-precedence-vs-PATH() {
+    local -r tmp=$1
+    local -r test_bin=$2
+
+    local -r sibling="$tmp/openresty/bin/nginx"
+
+    # setup PATH version
+    local -r path="$tmp/path-search"
+    local -r in_path="$path/nginx"
+    setup-nginx "$in_path"
+    export PATH=${path}:$PATH
+    expect-PATH nginx "$in_path"
+
+    local resty=$tmp/openresty/bin/resty
+    copy-binary "$test_bin" "$resty"
+
+    # PATH first
+    expect-nginx "$in_path" "$resty"
+
+    # sibling takes precedence if it exists
+    setup-nginx "$sibling"
+    expect-PATH nginx "$in_path"
+    expect-nginx "$sibling" "$resty"
+}
+
+test::sibling-nginx-via-symlink() {
+    local -r tmp=$1
+    local -r test_bin=$2
+
+    local -r nginx="$tmp/openresty/bin/nginx"
+    setup-nginx "$nginx"
+
+    local resty=$tmp/openresty/bin/resty
+    local resty_link="$tmp/symlinks-resty/resty"
+    copy-binary "$test_bin" "$resty"
+    symlink "$resty" "$resty_link"
+
+    expect-nginx "$nginx" "$resty"
+}
+
+test::nginx-in-PATH() {
+    local -r tmp=$1
+    local -r test_bin=$2
+
+    local -r path=$tmp/a/b/c
+    local -r nginx="$path/nginx"
+    setup-nginx "$nginx"
+
+    local resty=$tmp/openresty/bin/resty
+    copy-binary "$test_bin" "$resty"
+
+    export PATH=${path}:$PATH
+    expect-PATH nginx "$nginx"
+
+    expect-nginx "$nginx" "$resty"
+}
+
+for test in $(compgen -A function test::); do
+    name=${test#*::}
+    run-test "$name" "$test"
+done
+
+if (( ${#FAILED[@]} > 0 )); then
+    echo "Test failures:"
+    for name in "${FAILED[@]}"; do
+        echo "  - $name"
+    done
+
+    exit 1
+
+elif (( RAN == 0 )); then
+    echo "Something's wrong, no tests were executed?"
+    exit 1
+
+else
+    echo "OK"
+fi
diff --git a/tests/print-argv0 b/tests/print-argv0
new file mode 100755
index 0000000..ffbcf5e
--- /dev/null
+++ b/tests/print-argv0
@@ -0,0 +1,3 @@
+#!/usr/bin/env bash
+
+printf '%s' "$0"