diff --git a/config/thisroot.sh b/config/thisroot.sh
index d2ce449a5ea08..15357095d8cbe 100644
--- a/config/thisroot.sh
+++ b/config/thisroot.sh
@@ -173,7 +173,7 @@ getTrueShellExeName() { # mklement0 https://stackoverflow.com/a/23011530/7471760
    local trueExe nextTarget 2>/dev/null # ignore error in shells without `local`
    # Determine the shell executable filename.
    if [ -r "/proc/$$/cmdline" ]; then
-      trueExe=$(cut -d '' -f1 /proc/$$/cmdline 2>/dev/null) || trueExe=$(xargs -0 -n 1 < /proc/$$/cmdline | head -n 1) || return 1
+      trueExe=$(tr '\0' '\n' < /proc/$$/cmdline 2>/dev/null | sed -n '1p') || trueExe=$(xargs -0 -n 1 < /proc/$$/cmdline | head -n 1) || return 1
       # Qemu emulation has cmdline start with the emulator
       if [ "${trueExe##*qemu*}" != "${trueExe}" ]; then
          # but qemu sets comm to the emulated command
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 2eebde410858f..331fad5c0f1ac 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -12,6 +12,17 @@ set(root_exe $<TARGET_FILE:root.exe>)
 #---environment-------------------------------------------------------------------------------
 ROOT_ADD_TEST(show-environment COMMAND ${CMAKE_COMMAND} -E environment)
 
+if(thisroot_scripts AND CMAKE_SYSTEM_NAME STREQUAL "Linux")
+  foreach(shell IN ITEMS bash zsh)
+    find_program(THISROOT_${shell}_EXECUTABLE NAMES ${shell})
+    if(THISROOT_${shell}_EXECUTABLE)
+      ROOT_ADD_TEST(test-thisroot-${shell}
+                    COMMAND ${THISROOT_${shell}_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/testThisroot.sh
+                            ${THISROOT_${shell}_EXECUTABLE} ${CMAKE_BINARY_DIR})
+    endif()
+  endforeach()
+endif()
+
 #---hworld------------------------------------------------------------------------------------
 ROOT_EXECUTABLE(hworld hworld.cxx LIBRARIES Gpad)
 
diff --git a/test/testThisroot.sh b/test/testThisroot.sh
new file mode 100644
index 0000000000000..cf30ede31163e
--- /dev/null
+++ b/test/testThisroot.sh
@@ -0,0 +1,32 @@
+#!/bin/sh
+
+set -eu
+
+shell=$1
+root_dir=$2
+shell_name=${shell##*/}
+unset ROOTSYS
+
+# Variables are expanded by the child shell.
+# shellcheck disable=SC2016
+shell_command='
+if [ -n "${BASH_VERSION-}" ]; then shopt -s extdebug; fi;
+. "$1/bin/thisroot.sh" || exit 1;
+test "$ROOTSYS" = "$1" || exit 1;
+test "$SHELLNAME" = "$2" || exit 1;
+'
+
+single_line_command=$(printf '%s' "$shell_command" | tr '\n' ' ')
+
+for layout in single multiline long; do
+   printf 'Checking %s with %s commands\n' "$shell_name" "$layout"
+   case "$layout" in
+      single) command_text=$single_line_command ;;
+      multiline) command_text=$shell_command ;;
+      long)
+         padding=$(printf '%65536s' '')
+         command_text="set -o pipefail; $single_line_command #$padding"
+         ;;
+   esac
+   "$shell" -c "$command_text" thisroot-test "$root_dir" "$shell_name"
+done