Merge pull request #583 from danielb2/which

Adds `nvm which`

README.markdown

@@ -61,6 +61,10 @@ Or, you can run any arbitrary command in a subshell with the desired version of
 
     nvm exec 0.10 node --version
 
+You can also get the path to the executable to where it was installed:
+
+    nvm which 0.10
+
 In place of a version pointer like "0.10", you can use the special default aliases "stable" and "unstable":
 
     nvm install stable

nvm.sh

@@ -547,6 +547,7 @@ nvm() {
       echo "  nvm unalias <name>                    Deletes the alias named <name>"
       echo "  nvm reinstall-packages <version>      Reinstall global \`npm\` packages contained in <version> to current version"
       echo "  nvm unload                            Unload \`nvm\` from shell"
+      echo "  nvm which [<version>]                 Display path to installed node version"
       echo
       echo "Example:"
       echo "  nvm install v0.10.32                  Install a specific version number"
@@ -946,6 +947,43 @@ nvm() {
     "current" )
       nvm_version current
     ;;
+    "which" )
+      if [ $# -eq 1 ]; then
+        nvm_rc_version
+        if [ -n "$NVM_RC_VERSION" ]; then
+          VERSION=$(nvm_version $NVM_RC_VERSION)
+        fi
+      elif [ "_$2" != '_system' ]; then
+        VERSION="$(nvm_version "$2")"
+      else
+        VERSION="$2"
+      fi
+      if [ -z "$VERSION" ]; then
+        nvm help
+        return 127
+      fi
+
+      if [ "_$VERSION" = '_system' ]; then
+        if nvm_has_system_node >/dev/null 2>&1; then
+          echo $(nvm use system && echo dirname $(which node))
+          return
+        else
+          echo "System version of node not found." >&2
+          return 127
+        fi
+      elif [ "_$VERSION" = "_∞" ]; then
+        echo "The alias \"$2\" leads to an infinite loop. Aborting." >&2
+        return 8
+      fi
+
+      local NVM_VERSION_DIR
+      NVM_VERSION_DIR="$(nvm_version_path "$VERSION")"
+      if [ ! -d "$NVM_VERSION_DIR" ]; then
+        echo "$VERSION version is not installed yet" >&2
+        return 1
+      fi
+      echo $NVM_DIR/$VERSION/bin
+    ;;
     "alias" )
       mkdir -p "$NVM_DIR/alias"
       if [ $# -le 2 ]; then

test/fast/Listing paths/Running "nvm which 0.0.2" should display only version 0.0.2.

@@ -0,0 +1,20 @@
+#!/bin/sh
+
+mkdir ../../../v0.0.2
+mkdir ../../../v0.0.20
+
+. ../../../nvm.sh
+
+die () { echo $@ ; exit 1; }
+
+# The result should contain only the appropriate version numbers.
+
+nvm which 0.0.2 | grep "$NVM_DIR/v0.0.2/bin" > /dev/null
+if [ $? -ne 0 ]; then
+  die '"nvm which 0.0.2" did not contain the correct path'
+fi
+
+nvm which 0.0.20 | grep "$NVM_DIR/v0.0.20/bin" > /dev/null
+if [ $? -ne 0 ]; then
+  die '"nvm which 0.0.2" did not contain the correct path'
+fi

test/fast/Listing paths/Running "nvm which foo" should return a nonzero exit code when not found

@@ -0,0 +1,6 @@
+ #!/bin/sh
+
+. ../../../nvm.sh
+
+nvm which nonexistent_version
+[ "$?" = "1" ]

test/fast/Listing paths/teardown

@@ -0,0 +1,2 @@
+rmdir ../../../v0.0.2 >/dev/null 2>&1
+rmdir ../../../v0.0.20 >/dev/null 2>&1