diff --git a/nvm.sh b/nvm.sh
index 3169711..2042a24 100644
--- a/nvm.sh
+++ b/nvm.sh
@@ -2576,7 +2576,7 @@ $NVM_LS_REMOTE_POST_MERGED_OUTPUT" | nvm_grep -v "N/A" | command sed '/^$/d')"
         nvm_version_greater nvm_version_greater_than_or_equal_to \
         nvm_print_npm_version nvm_npm_global_modules \
         nvm_has_system_node nvm_has_system_iojs \
-        nvm_download nvm_get_latest nvm_has nvm_get_latest \
+        nvm_download nvm_get_latest nvm_has \
         nvm_supports_source_options nvm_auto nvm_supports_xz \
         nvm_echo nvm_err nvm_grep \
         nvm_has_colors nvm_process_parameters > /dev/null 2>&1
diff --git "a/test/fast/Running \"nvm alias\" should create a file in the alias directory." "b/test/fast/Running \"nvm alias\" should create a file in the alias directory."
index 38ba260..8a466bb 100755
--- "a/test/fast/Running \"nvm alias\" should create a file in the alias directory."	
+++ "b/test/fast/Running \"nvm alias\" should create a file in the alias directory."	
@@ -1,5 +1,9 @@
 #!/bin/sh
 
+set -ex
+
 . ../../nvm.sh
+
 nvm alias test v0.1.2
-[ "$(cat ../../alias/test)" = "v0.1.2" ]
+
+[ "$(cat "$(nvm_alias_path)/test")" = "v0.1.2" ]
diff --git "a/test/fast/Running \"nvm current\" should display current nvm environment." "b/test/fast/Running \"nvm current\" should display current nvm environment."
index 5748fd6..db87520 100755
--- "a/test/fast/Running \"nvm current\" should display current nvm environment."	
+++ "b/test/fast/Running \"nvm current\" should display current nvm environment."	
@@ -1,5 +1,7 @@
 #!/bin/sh
 
+set -ex
+
 die () { echo $@ ; exit 1; }
 
 . ../../nvm.sh
@@ -7,4 +9,3 @@ die () { echo $@ ; exit 1; }
 nvm deactivate 2>&1
 
 [ "$(nvm current)" = "system" ] || [ "$(nvm current)" = "none" ] || die '"nvm current" did not report "system" or "none" when deactivated'
-
diff --git "a/test/fast/Running \"nvm deactivate\" should unset the nvm environment variables." "b/test/fast/Running \"nvm deactivate\" should unset the nvm environment variables."
index 0356276..ba51074 100755
--- "a/test/fast/Running \"nvm deactivate\" should unset the nvm environment variables."	
+++ "b/test/fast/Running \"nvm deactivate\" should unset the nvm environment variables."	
@@ -1,5 +1,7 @@
 #!/bin/sh
 
+set -ex
+
 mkdir -p ../../v0.2.3
 
 die () { echo $@ ; exit 1; }
@@ -7,6 +9,7 @@ die () { echo $@ ; exit 1; }
 [ `expr $PATH : ".*v0.2.3/.*/bin"` = 0 ] || echo "WARNING: Unexpectedly found v0.2.3 already active" >&2
 
 . ../../nvm.sh
+
 nvm use --delete-prefix v0.2.3 || die "Failed to activate v0.2.3"
 [ `expr "$PATH" : ".*v0.2.3/.*/bin"` != 0 ] || die "PATH not set up properly"
 [ `expr "$NODE_PATH" : ".*v0.2.3/.*/lib/node_modules"` = 0 ] || die "NODE_PATH should not contain (npm root -g)"
diff --git "a/test/fast/Running \"nvm install\" with \"--reinstall-packages-from\" requires a valid version" "b/test/fast/Running \"nvm install\" with \"--reinstall-packages-from\" requires a valid version"
index c6d2c33..f7b016d 100755
--- "a/test/fast/Running \"nvm install\" with \"--reinstall-packages-from\" requires a valid version"	
+++ "b/test/fast/Running \"nvm install\" with \"--reinstall-packages-from\" requires a valid version"	
@@ -1,5 +1,7 @@
 #!/bin/sh
 
+set -ex
+
 die () { echo $@ ; cleanup ; exit 1; }
 cleanup () {
   rm -rf "${NVM_DIR}/v0.10.4"
@@ -11,22 +13,30 @@ mkdir "${NVM_DIR}/v0.10.4"
 
 nvm deactivate >/dev/null 2>&1
 
+set +ex # needed for stderr
 INSTALL_ERROR_MSG="$(nvm install v0.10.5 --reinstall-packages-from=0.11 2>&1)"
+set -ex
 EXPECTED_ERROR_MSG="If --reinstall-packages-from is provided, it must point to an installed version of node."
 [ "~$INSTALL_ERROR_MSG" = "~$EXPECTED_ERROR_MSG" ] \
   || die ""nvm install --reinstall-packages-from" should fail when given an uninstalled version: expected '$EXPECTED_ERROR_MSG', got '$INSTALL_ERROR_MSG'"
 
+set +e # TODO: fix
 INSTALL_EXIT_CODE="$(nvm install v0.10.5 --reinstall-packages-from=0.11 >/dev/null 2>&1; echo $?)"
-[ "~$INSTALL_EXIT_CODE" = "~5" ] \
-  || die ""nvm install --reinstall-packages-from" should exit with code 5 when given an uninstalled version, got $INSTALL_EXIT_CODE"
+set -e
+[ $INSTALL_EXIT_CODE -eq 5 ] \
+  || die ""nvm install --reinstall-packages-from" should exit with code 5 when given an uninstalled version, got ${INSTALL_EXIT_CODE}"
 
+set +ex # needed for stderr
 INSTALL_ERROR_MSG="$(nvm install v0.10.5 --reinstall-packages-from=0.10.5 2>&1)"
+set -ex
 EXPECTED_ERROR_MSG="You can't reinstall global packages from the same version of node you're installing."
 [ "~$INSTALL_ERROR_MSG" = "~$EXPECTED_ERROR_MSG" ] \
   || die ""nvm install --reinstall-packages-from" should fail when given the same version: expected '$EXPECTED_ERROR_MSG', got '$INSTALL_ERROR_MSG'"
 
+set +e # TODO: fix
 INSTALL_EXIT_CODE="$(nvm install v0.10.5 --reinstall-packages-from=0.10.5 >/dev/null 2>&1; echo $?)"
-[ "~$INSTALL_EXIT_CODE" = "~4" ] \
+set -e
+[ $INSTALL_EXIT_CODE -eq 4 ] \
   || die ""nvm install --reinstall-packages-from" should exit with code 4 when given the same version, got $INSTALL_EXIT_CODE"
 
 cleanup
diff --git "a/test/fast/Running \"nvm install\" with an invalid version fails nicely" "b/test/fast/Running \"nvm install\" with an invalid version fails nicely"
index d113890..3d78340 100755
--- "a/test/fast/Running \"nvm install\" with an invalid version fails nicely"	
+++ "b/test/fast/Running \"nvm install\" with an invalid version fails nicely"	
@@ -1,7 +1,13 @@
 #!/bin/sh
 
+set -ex
+
 die () { echo $@ ; exit 1; }
 
 . ../../nvm.sh
-[ "$(nvm install invalid.invalid 2>&1)" = "Version 'invalid.invalid' not found - try \`nvm ls-remote\` to browse available versions." ] || die "nvm installing an invalid version did not print a nice error message"
 
+set +ex # needed for stderr
+OUTPUT="$(nvm install invalid.invalid 2>&1)"
+set -ex
+EXPECTED_OUTPUT="Version 'invalid.invalid' not found - try \`nvm ls-remote\` to browse available versions."
+[ "${OUTPUT}" = "${EXPECTED_OUTPUT}" ] || die "nvm installing an invalid version did not print a nice error message"
diff --git "a/test/fast/Running \"nvm unalias\" should remove the alias file." "b/test/fast/Running \"nvm unalias\" should remove the alias file."
index f8ed49d..d49ebf2 100755
--- "a/test/fast/Running \"nvm unalias\" should remove the alias file."	
+++ "b/test/fast/Running \"nvm unalias\" should remove the alias file."	
@@ -1,6 +1,13 @@
 #!/bin/sh
 
-echo v0.1.2 > ../../alias/test
+set -ex
+
+ALIAS_PATH="../../alias"
+
+echo v0.1.2 > "${ALIAS_PATH}/test"
+
 . ../../nvm.sh
+
 nvm unalias test
-! [ -e ../../alias/test ]
+
+! [ -e "${ALIAS_PATH}/test" ]
diff --git "a/test/fast/Running \"nvm uninstall\" should remove the appropriate directory." "b/test/fast/Running \"nvm uninstall\" should remove the appropriate directory."
index ba1ddbb..0123ab7 100755
--- "a/test/fast/Running \"nvm uninstall\" should remove the appropriate directory."	
+++ "b/test/fast/Running \"nvm uninstall\" should remove the appropriate directory."	
@@ -1,5 +1,7 @@
 #!/bin/sh
 
+set -ex
+
 cd ../..
 mkdir v0.0.1
 mkdir src/node-v0.0.1
diff --git "a/test/fast/Running \"nvm uninstall\" with incorrect file permissions fails nicely" "b/test/fast/Running \"nvm uninstall\" with incorrect file permissions fails nicely"
index 1fad640..5fd2638 100755
--- "a/test/fast/Running \"nvm uninstall\" with incorrect file permissions fails nicely"	
+++ "b/test/fast/Running \"nvm uninstall\" with incorrect file permissions fails nicely"	
@@ -1,5 +1,7 @@
 #!/bin/sh
 
+set -ex
+
 cd ../..
 mkdir v0.0.1
 mkdir src/node-v0.0.1
@@ -8,7 +10,7 @@ sudo touch v0.0.1/sudo
 
 . ./nvm.sh
 
-RETURN_MESSAGE="$(nvm uninstall v0.0.1 2>&1)"
+RETURN_MESSAGE="$(nvm uninstall v0.0.1 2>&1 || echo)"
 CHECK_FOR="Cannot uninstall, incorrect permissions on installation folder"
 
-test "${RETURN_MESSAGE#*$CHECK_FOR}" != "$RETURN_MESSAGE" || exit 1
+[ "${RETURN_MESSAGE#*$CHECK_FOR}" != "$RETURN_MESSAGE" ] || exit 1
diff --git "a/test/fast/Running \"nvm unload\" should unset all function and variables." "b/test/fast/Running \"nvm unload\" should unset all function and variables."
index 0f4c50e..3ac3505 100755
--- "a/test/fast/Running \"nvm unload\" should unset all function and variables."	
+++ "b/test/fast/Running \"nvm unload\" should unset all function and variables."	
@@ -1,12 +1,13 @@
 #!/bin/sh
 
-fail () { echo $@ ; exit 1; }
+set -ex
+
+die () { echo $@ ; exit 1; }
 
 . ../../nvm.sh
 
-type nvm > /dev/null 2>&1 || fail "NVM not loaded"
+type nvm > /dev/null 2>&1 || die "nvm not loaded"
 
 nvm unload
 
-type nvm > /dev/null 2>&1 && fail "NVM not unloaded" || exit 0
-
+! type nvm > /dev/null 2>&1 || die "nvm not unloaded"
diff --git "a/test/fast/Running \"nvm use foo\" where \"foo\" is circular aborts" "b/test/fast/Running \"nvm use foo\" where \"foo\" is circular aborts"
index ce4fea4..023415c 100755
--- "a/test/fast/Running \"nvm use foo\" where \"foo\" is circular aborts"	
+++ "b/test/fast/Running \"nvm use foo\" where \"foo\" is circular aborts"	
@@ -1,5 +1,7 @@
 #!/bin/sh
 
+set -ex
+
 die () { echo $@ ; cleanup ; exit 1; }
 
 cleanup() {
@@ -10,20 +12,28 @@ cleanup() {
 
 nvm_make_alias foo foo
 
+set +ex # needed for stderr
 OUTPUT="$(nvm use foo 2>&1)"
+set -ex
 EXPECTED_OUTPUT='The alias "foo" leads to an infinite loop. Aborting.'
 [ "_${OUTPUT}" = "_${EXPECTED_OUTPUT}" ] \
   || die "'nvm use foo' did not output >${EXPECTED_OUTPUT}<; got >${OUTPUT}<"
 
+set +ex # needed for stderr
 EXIT_CODE="$(nvm use foo 2>/dev/null ; echo $?)"
+set -ex
 [ "_$EXIT_CODE" = "_8" ] || die "Expected exit code 8; got ${EXIT_CODE}"
 
+set +ex # needed for stderr
 OUTPUT="$(nvm use --silent foo 2>&1)"
+set -ex
 EXPECTED_OUTPUT=''
 [ "_${OUTPUT}" = "_${EXPECTED_OUTPUT}" ] \
   || die "'nvm use --silent foo' did not output >${EXPECTED_OUTPUT}<; got >${OUTPUT}<"
 
+set +ex # needed for stderr
 EXIT_CODE="$(nvm use --silent foo 2>/dev/null ; echo $?)"
+set -ex
 [ $EXIT_CODE -eq 8 ] || die "Expected exit code 8 from 'nvm use --silent foo'; got ${EXIT_CODE}"
 
 cleanup
diff --git "a/test/fast/Running \"nvm use iojs\" uses latest io.js version" "b/test/fast/Running \"nvm use iojs\" uses latest io.js version"
index 1a44d93..6c54203 100755
--- "a/test/fast/Running \"nvm use iojs\" uses latest io.js version"	
+++ "b/test/fast/Running \"nvm use iojs\" uses latest io.js version"	
@@ -13,9 +13,7 @@ cleanup() {
   rm -rf "$(nvm_version_path "iojs-${VERSION}")"
 }
 
-set +ex # TODO
 . ../../nvm.sh
-set -ex
 
 nvm deactivate || die "unable to deactivate; current: >$(nvm current)<"
 
diff --git "a/test/fast/Running \"nvm use system\" should work as expected" "b/test/fast/Running \"nvm use system\" should work as expected"
index 46875ac..196353d 100755
--- "a/test/fast/Running \"nvm use system\" should work as expected"	
+++ "b/test/fast/Running \"nvm use system\" should work as expected"	
@@ -1,5 +1,7 @@
 #!/bin/sh
 
+set -ex
+
 cleanup() {
   unset -f nvm_has_system_node nvm_print_npm_version
 }
@@ -11,19 +13,32 @@ nvm_has_system_node() { return 0; }
 nvm_print_npm_version() { command printf ' (npm v1.2.3)'; }
 
 EXPECTED_OUTPUT="Now using system version of node: $(node -v)$(nvm_print_npm_version)"
+set +x # since stderr is needed
 OUTPUT="$(nvm use system 2>&1)"
+set -x
 [ "${OUTPUT}" = "${EXPECTED_OUTPUT}" ] || die "Could not use system version of node. Got >${OUTPUT}<, expected >${EXPECTED_OUTPUT}<"
+
 EXPECTED_OUTPUT=""
-[ "$(nvm use --silent system 2>&1 | tail -1)" = "${EXPECTED_OUTPUT}" ] || die "Could not use system version of node or --silent was not silent"
+set +x # since stderr is needed
+OUTPUT="$(nvm use --silent system 2>&1 | tail -1)"
+set -x
+[ "${OUTPUT}" = "${EXPECTED_OUTPUT}" ] || die "Could not use system version of node or --silent was not silent"
 
 nvm_has_system_node() { return 1; }
 nvm_print_npm_version() { command printf ''; }
 
 EXPECTED_OUTPUT="System version of node not found."
-[ "$(nvm use system 2>&1 | tail -1)" = "${EXPECTED_OUTPUT}" ] || die "Did not report error, system node not found"
+set +x # since stderr is needed
+OUTPUT="$(nvm use system 2>&1 | tail -1)"
+set -x
+[ "${OUTPUT}" = "${EXPECTED_OUTPUT}" ] || die "Did not report error, system node not found"
+
 nvm use system 2>&1 > /dev/null || [ $? -eq 127 ] || die "Did not return error code, system node not found"
 EXPECTED_OUTPUT=""
-[ "$(nvm use --silent system 2>&1 | tail -1)" = "${EXPECTED_OUTPUT}" ] || die "Did not report error, system node not found or --silent was not silent"
+set +x # since stderr is needed
+OUTPUT="$(nvm use --silent system 2>&1 | tail -1)"
+set -x
+[ "${OUTPUT}" = "${EXPECTED_OUTPUT}" ] || die "Did not report error, system node not found or --silent was not silent"
 nvm use --silent system 2>&1 > /dev/null || [ $? -eq 127 ] || die "Did not return error code, system node not found or --silent was not silent"
 
 cleanup
diff --git "a/test/fast/Running \"nvm use x\" should create and change the \"current\" symlink" "b/test/fast/Running \"nvm use x\" should create and change the \"current\" symlink"
index 8ddaedc..e600497 100755
--- "a/test/fast/Running \"nvm use x\" should create and change the \"current\" symlink"	
+++ "b/test/fast/Running \"nvm use x\" should create and change the \"current\" symlink"	
@@ -1,11 +1,13 @@
-#!/usr/bin/env bash
+#!/bin/sh
+
+set -ex
 
 export NVM_SYMLINK_CURRENT=true
 . ../../nvm.sh
 
 rm -rf "${NVM_DIR}/v0.10.29"
 mkdir "${NVM_DIR}/v0.10.29"
-nvm use 0.10.29
+nvm use --delete-prefix 0.10.29
 rmdir "${NVM_DIR}/v0.10.29"
 
 if [ ! -L "${NVM_DIR}/current" ];then
@@ -22,7 +24,7 @@ fi
 
 rm -rf "${NVM_DIR}/v0.11.13"
 mkdir "${NVM_DIR}/v0.11.13"
-nvm use 0.11.13
+nvm use --delete-prefix 0.11.13
 rmdir "${NVM_DIR}/v0.11.13"
 
 newLink="$(readlink "${NVM_DIR}/current")"
diff --git "a/test/fast/Running \"nvm use x\" should not create the \"current\" symlink if $NVM_SYMLINK_CURRENT is false" "b/test/fast/Running \"nvm use x\" should not create the \"current\" symlink if $NVM_SYMLINK_CURRENT is false"
index 3603e04..b84ebf4 100755
--- "a/test/fast/Running \"nvm use x\" should not create the \"current\" symlink if $NVM_SYMLINK_CURRENT is false"	
+++ "b/test/fast/Running \"nvm use x\" should not create the \"current\" symlink if $NVM_SYMLINK_CURRENT is false"	
@@ -1,4 +1,6 @@
-#!/usr/bin/env bash
+#!/bin/sh
+
+set -ex
 
 . ../../nvm.sh
 
@@ -8,17 +10,17 @@ TEST_COUNT=0
 TEST_PASSED=0
 TEST_FAILED=0
 
-function registerExpectedSymlink() {
+registerExpectedSymlink() {
   registerResult ${1}
 }
 
-function registerExpectedNoSymlink() {
-  [ ${1} -ne 0 ]
+registerExpectedNoSymlink() {
+  [ $1 -ne 0 ]
   registerResult $?
 }
 
-function registerResult() {
-  result=${1}
+registerResult() {
+  result="${1}"
 
   TEST_COUNT=$(($TEST_COUNT + 1))
 
@@ -27,19 +29,19 @@ function registerResult() {
     || TEST_FAILED=$(($TEST_FAILED + 1))
 }
 
-function cleanup() {
-  rm -rf ../../${TEST_NODE_VERSION}
-  rm -f ../../current
+cleanup() {
+  rm -rf "${NVM_DIR}/${TEST_NODE_VERSION}"
+  rm -f "${NVM_DIR}/current"
 }
 
-function runNvmUse() {
-  mkdir ../../${TEST_NODE_VERSION}
-  nvm use ${TEST_NODE_VERSION} > /dev/null 2>&1
-  rmdir ../../${TEST_NODE_VERSION}
+runNvmUse() {
+  mkdir "${NVM_DIR}/${TEST_NODE_VERSION}"
+  nvm use --delete-prefix "${TEST_NODE_VERSION}" > /dev/null 2>&1
+  rmdir "${NVM_DIR}/${TEST_NODE_VERSION}"
 }
 
-function isCurrentSymlinkPresent() {
-  [ -L ../../current ]
+isCurrentSymlinkPresent() {
+  [ -L "${NVM_DIR}/current" ]
 }
 
 NVM_SYMLINK_CURRENT=false
@@ -80,5 +82,4 @@ registerExpectedNoSymlink $?
 
 cleanup
 
-[ ${TEST_FAILED} -ne 0 ] && echo "${TEST_COUNT} tested, ${TEST_PASSED} passed, ${TEST_FAILED} failed" && exit 1 || true
-
+[ $TEST_FAILED -ne 0 ] && echo "${TEST_COUNT} tested, ${TEST_PASSED} passed, ${TEST_FAILED} failed" && exit 1 || true
diff --git a/test/fast/Sourcing nvm.sh should make the nvm command available. b/test/fast/Sourcing nvm.sh should make the nvm command available.
index 24f8efa..9c215d5 100755
--- a/test/fast/Sourcing nvm.sh should make the nvm command available.	
+++ b/test/fast/Sourcing nvm.sh should make the nvm command available.	
@@ -1,4 +1,7 @@
 #!/bin/sh
 
+set -ex
+
 . ../../nvm.sh
+
 nvm
diff --git a/test/fast/Sourcing nvm.sh should not modify parameters of caller b/test/fast/Sourcing nvm.sh should not modify parameters of caller
index 67e88cf..cf8b149 100755
--- a/test/fast/Sourcing nvm.sh should not modify parameters of caller	
+++ b/test/fast/Sourcing nvm.sh should not modify parameters of caller	
@@ -1,5 +1,7 @@
 #!/bin/sh
 
+set -ex
+
 set -- yes
 . ../../nvm.sh
 [ "$1" = yes ]
diff --git a/test/fast/setup b/test/fast/setup
index f98394b..6de3378 100755
--- a/test/fast/setup
+++ b/test/fast/setup
@@ -1,5 +1,7 @@
 #!/bin/sh
 
+set -ex
+
 (
   cd ../..
 
diff --git a/test/fast/setup_dir b/test/fast/setup_dir
index 5e2a208..fd36775 100755
--- a/test/fast/setup_dir
+++ b/test/fast/setup_dir
@@ -1,5 +1,7 @@
 #!/bin/sh
 
+set -ex
+
 (
   cd ../..
 
diff --git a/test/fast/teardown b/test/fast/teardown
index a1c73df..75a406e 100755
--- a/test/fast/teardown
+++ b/test/fast/teardown
@@ -1,5 +1,7 @@
 #!/bin/sh
 
+set -ex
+
 # Remove temporary files
 (
   cd ../..
diff --git a/test/fast/teardown_dir b/test/fast/teardown_dir
index 065269a..9efb49e 100755
--- a/test/fast/teardown_dir
+++ b/test/fast/teardown_dir
@@ -1,5 +1,7 @@
 #!/bin/sh
 
+set -ex
+
 (
   cd ../..