diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index c5b62fd..9ea8193 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -153,7 +153,7 @@ All JuNest issues are tracked as [GitHub issues](https://guides.github.com/featu
 #### Unit Tests ####
 To run unit tests:
 ```sh
-./tests/unit-tests.sh
+./tests/unit-tests/unit-tests.sh
 ```
 
 #### Integration Tests ####
diff --git a/lib/core.sh b/lib/core.sh
index 7012391..dbb81d2 100644
--- a/lib/core.sh
+++ b/lib/core.sh
@@ -87,6 +87,8 @@ CHOWN="chown"
 LN=ln
 RM=rm
 MKDIR=mkdir
+GETENT=getent
+CP=cp
 
 LD_EXEC="$LD_LIB --library-path ${JUNEST_HOME}/usr/lib:${JUNEST_HOME}/lib"
 
@@ -98,6 +100,14 @@ function ln_cmd(){
     $LN $@ || $LD_EXEC ${JUNEST_HOME}/usr/bin/$LN $@
 }
 
+function getent_cmd(){
+    $GETENT $@ || $LD_EXEC ${JUNEST_HOME}/usr/bin/$GETENT $@
+}
+
+function cp_cmd(){
+    $CP $@ || $LD_EXEC ${JUNEST_HOME}/usr/bin/$CP $@
+}
+
 function rm_cmd(){
     $RM $@ || $LD_EXEC ${JUNEST_HOME}/usr/bin/$RM $@
 }
@@ -357,6 +367,7 @@ function run_env_as_user(){
     (( EUID == 0 )) && \
         die_on_status $ROOT_ACCESS_ERROR "You cannot access with root privileges. Use --root option instead."
 
+    _build_passwd_and_group
     _provide_bindings_as_user
     local bindings="$RESULT"
     unset RESULT
@@ -365,6 +376,9 @@ function run_env_as_user(){
 
 #######################################
 # Provide the proot binding options for the normal user.
+# The list of bindings can be found in `proot --help`. This function excludes
+# /etc/mtab file so that it will not give conflicts with the related
+# symlink in the image.
 #
 # Globals:
 #   HOME (RO)       : The home directory.
@@ -377,16 +391,48 @@ function run_env_as_user(){
 #   None
 #######################################
 function _provide_bindings_as_user(){
-    # The list of bindings can be found in `proot --help`. This function excludes
-    # /etc/mtab file so that it will not give conflicts with the related
-    # symlink in the image.
     RESULT=""
-    for bind in "/etc/host.conf" "/etc/hosts" "/etc/hosts.equiv" "/etc/netgroup" "/etc/networks" "/etc/passwd" "/etc/group" "/etc/nsswitch.conf" "/etc/resolv.conf" "/etc/localtime" "/dev" "/sys" "/proc" "/tmp" "$HOME"
+    local re='(.*):.*'
+    for bind in "/etc/host.conf" "/etc/hosts" "/etc/hosts.equiv" "/etc/netgroup" "/etc/networks" "${JUNEST_HOME}/etc/junest/passwd:/etc/passwd" "${JUNEST_HOME}/etc/junest/group:/etc/group" "/etc/nsswitch.conf" "/etc/resolv.conf" "/etc/localtime" "/dev" "/sys" "/proc" "/tmp" "$HOME"
     do
-        [ -e "$bind" ] && RESULT="-b $bind $RESULT"
+        if [[ $bind =~ $re ]]
+        then
+            [ -e "${BASH_REMATCH[1]}" ] && RESULT="-b $bind $RESULT"
+        else
+            [ -e "$bind" ] && RESULT="-b $bind $RESULT"
+        fi
     done
 }
 
+#######################################
+# Build passwd and group files using getent command.
+# If getent fails the function fallbacks by copying the content from /etc/passwd
+# and /etc/group.
+#
+# The generated passwd and group will be stored in $JUNEST_HOME/etc/junest.
+#
+# Globals:
+#  JUNEST_HOME (RO)      : The JuNest home directory.
+# Arguments:
+#  None
+# Returns:
+#  None
+# Output:
+#  None
+#######################################
+function _build_passwd_and_group(){
+    if ! getent_cmd passwd > ${JUNEST_HOME}/etc/junest/passwd
+    then
+        warn "getent command failed or does not exist. Binding directly from /etc/passwd."
+        cp_cmd /etc/passwd ${JUNEST_HOME}/etc/junest/passwd
+    fi
+    if ! getent_cmd group > ${JUNEST_HOME}/etc/junest/group
+    then
+        warn "getent command failed or does not exist. Binding directly from /etc/group."
+        cp_cmd /etc/group ${JUNEST_HOME}/etc/junest/group
+    fi
+}
+
 #######################################
 # Remove an existing JuNest system.
 #
diff --git a/tests/unit-tests/test-core.sh b/tests/unit-tests/test-core.sh
index 46072e1..a009510 100755
--- a/tests/unit-tests/test-core.sh
+++ b/tests/unit-tests/test-core.sh
@@ -55,6 +55,26 @@ function test_ln(){
     LN=false LD_EXEC=false assertCommandFail ln_cmd
 }
 
+function test_getent(){
+    GETENT=echo assertCommandSuccess getent_cmd passwd
+    assertEquals "passwd" "$(cat $STDOUTF)"
+
+    GETENT=false assertCommandSuccess getent_cmd passwd
+    assertEquals "ld_exec ${JUNEST_HOME}/usr/bin/false passwd" "$(cat $STDOUTF)"
+
+    GETENT=false LD_EXEC=false assertCommandFail getent_cmd
+}
+
+function test_cp(){
+    CP=echo assertCommandSuccess cp_cmd passwd
+    assertEquals "passwd" "$(cat $STDOUTF)"
+
+    CP=false assertCommandSuccess cp_cmd passwd
+    assertEquals "ld_exec ${JUNEST_HOME}/usr/bin/false passwd" "$(cat $STDOUTF)"
+
+    CP=false LD_EXEC=false assertCommandFail cp_cmd
+}
+
 function test_download(){
     WGET=/bin/true
     CURL=/bin/false
@@ -222,6 +242,45 @@ function test_run_env_as_user(){
     assertEquals "${RESULT}-r ${JUNEST_HOME} -k 3.10" "$(cat $STDOUTF)"
 }
 
+function test_provide_bindings_as_user_no_junest_home(){
+    _provide_bindings_as_user
+    echo "$RESULT" | grep -q "$JUNEST_HOME/etc/junest/passwd"
+    assertEquals 1 $?
+    echo "$RESULT" | grep -q "$JUNEST_HOME/etc/junest/group"
+    assertEquals 1 $?
+}
+
+function test_provide_bindings_as_user(){
+    touch $JUNEST_HOME/etc/junest/passwd
+    touch $JUNEST_HOME/etc/junest/group
+    _provide_bindings_as_user
+    echo "$RESULT" | grep -q "$JUNEST_HOME/etc/junest/passwd"
+    assertEquals 0 $?
+    echo "$RESULT" | grep -q "$JUNEST_HOME/etc/junest/group"
+    assertEquals 0 $?
+}
+
+function test_build_passwd_and_group(){
+    getent_cmd_mock() {
+        echo $@
+    }
+    GETENT=getent_cmd_mock assertCommandSuccess _build_passwd_and_group
+    assertEquals "passwd" "$(cat $JUNEST_HOME/etc/junest/passwd)"
+    assertEquals "group" "$(cat $JUNEST_HOME/etc/junest/group)"
+}
+
+function test_build_passwd_and_group_fallback(){
+    cp_cmd_mock() {
+        echo $@
+    }
+    CP=cp_cmd_mock GETENT=false LD_EXEC=false assertCommandSuccess _build_passwd_and_group
+    assertEquals "$(echo -e "/etc/passwd $JUNEST_HOME/etc/junest/passwd\n/etc/group $JUNEST_HOME/etc/junest/group")" "$(cat $STDOUTF)"
+}
+
+function test_build_passwd_and_group_failure(){
+    CP=false GETENT=false LD_EXEC=false assertCommandFailOnStatus 1 _build_passwd_and_group
+}
+
 function test_run_env_as_fakeroot(){
     _run_env_with_qemu() {
         echo $@