Update the installation scripts in release/2.0.0 branch.

scripts/obtain/dotnet-install.sh

@@ -55,6 +55,9 @@ say_verbose() {
     fi
 }
 
+# This platform list is finite - if the SDK/Runtime has supported Linux distribution-specific assets,
+#   then and only then should the Linux distribution appear in this list.
+# Adding a Linux distribution to this list does not imply distribution-specific support.
 get_os_download_name_from_platform() {
     eval $invocation
 
@@ -84,6 +87,10 @@ get_os_download_name_from_platform() {
             echo "opensuse.42.1"
             return 0
             ;;
+        "rhel.6"*)
+            echo "rhel.6"
+            return 0
+            ;;
         "rhel.7"*)
             echo "rhel"
             return 0
@@ -115,8 +122,14 @@ get_current_os_name() {
     if [ "$uname" = "Darwin" ]; then
         echo "osx"
         return 0
-    else
-        if [ "$uname" = "Linux" ]; then
+    elif [ "$uname" = "Linux" ]; then
+        local distro_specific_osname
+        distro_specific_osname=$(get_distro_specific_os_name) || return 1
+
+        if [ "$distro_specific_osname" = "rhel.6" ]; then
+            echo $distro_specific_osname
+            return 0
+        else
             echo "linux"
             return 0
         fi
@@ -144,6 +157,12 @@ get_distro_specific_os_name() {
                 echo "$os"
                 return 0
             fi
+        elif [ -e /etc/redhat-release ]; then
+            local redhatRelease=$(</etc/redhat-release)
+            if [[ $redhatRelease == "CentOS release 6."* || $redhatRelease == "Red Hat Enterprise Linux Server release 6."* ]]; then
+                echo "rhel.6"
+                return 0
+            fi
         fi
     fi
     
@@ -191,9 +210,13 @@ check_pre_reqs() {
             LDCONFIG_COMMAND="ldconfig"
         fi
 
-        [ -z "$($LDCONFIG_COMMAND -p | grep libunwind)" ] && say_err "Unable to locate libunwind. Install libunwind to continue" && failing=true
-        [ -z "$($LDCONFIG_COMMAND -p | grep libssl)" ] && say_err "Unable to locate libssl. Install libssl to continue" && failing=true
-        [ -z "$($LDCONFIG_COMMAND -p | grep libicu)" ] && say_err "Unable to locate libicu. Install libicu to continue" && failing=true
+        local librarypath=${LD_LIBRARY_PATH:-}
+        LDCONFIG_COMMAND="$LDCONFIG_COMMAND -NXv ${LD_LIBRARY_PATH//:/ }"
+
+        [ -z "$($LDCONFIG_COMMAND | grep libunwind)" ] && say_err "Unable to locate libunwind. Install libunwind to continue" && failing=true
+        [ -z "$($LDCONFIG_COMMAND | grep libssl)" ] && say_err "Unable to locate libssl. Install libssl to continue" && failing=true
+        [ -z "$($LDCONFIG_COMMAND | grep libicu)" ] && say_err "Unable to locate libicu. Install libicu to continue" && failing=true
+        [ -z "$($LDCONFIG_COMMAND | grep -F libcurl.so)" ] && say_err "Unable to locate libcurl. Install libcurl to continue" && failing=true
     fi
 
     if [ "$failing" = true ]; then
@@ -333,6 +356,7 @@ is_dotnet_package_installed() {
 # azure_feed - $1
 # channel - $2
 # normalized_architecture - $3
+# coherent - $4
 get_latest_version_info() {
     eval $invocation
     
@@ -541,7 +565,7 @@ extract_dotnet_package() {
     
     local folders_with_version_regex='^.*/[0-9]+\.[0-9]+[^/]+/'
     find $temp_out_path -type f | grep -Eo $folders_with_version_regex | copy_files_or_dirs_from_list $temp_out_path $out_path false
-    find $temp_out_path -type f | grep -Ev $folders_with_version_regex | copy_files_or_dirs_from_list $temp_out_path $out_path true
+    find $temp_out_path -type f | grep -Ev $folders_with_version_regex | copy_files_or_dirs_from_list $temp_out_path $out_path $override_non_versioned_files
     
     rm -rf $temp_out_path
     
@@ -600,7 +624,7 @@ downloadwget() {
 
     local failed=false
     if [ -z "$out_path" ]; then
-        wget -q --tries 10 $remote_path || failed=true
+        wget -q --tries 10 -O - $remote_path || failed=true
     else
         wget -v --tries 10 -O $out_path $remote_path || failed=true
     fi
@@ -654,7 +678,9 @@ install_dotnet() {
     say_verbose "Zip path: $zip_path"
 
     say "Downloading link: $download_link"
-    download "$download_link" $zip_path || download_failed=true
+    # Failures are normal in the non-legacy case for ultimately legacy downloads.
+    # Do not output to stderr, since output to stderr is considered an error.
+    download "$download_link" $zip_path 2>&1 || download_failed=true
 
     #  if the download fails, download the legacy_download_link
     if [ "$download_failed" = true ] && [ "$valid_legacy_download_link" = true ]; then
@@ -687,6 +713,7 @@ uncached_feed="https://dotnetcli.blob.core.windows.net/dotnet"
 verbose=false
 shared_runtime=false
 runtime_id=""
+override_non_versioned_files=true
 
 while [ $# -ne 0 ]
 do
@@ -732,6 +759,10 @@ do
             shift
             runtime_id="$1"
             ;;
+        --skip-non-versioned-files|-[Ss]kip[Nn]on[Vv]ersioned[Ff]iles)
+            shift
+            override_non_versioned_files=false
+            ;;
         -?|--?|-h|--help|-[Hh]elp)
             script_name="$(basename $0)"
             echo ".NET Tools Installer"
@@ -764,6 +795,8 @@ do
             echo "      --arch,-Architecture,-Arch"
             echo "  --shared-runtime               Installs just the shared runtime bits, not the entire SDK."
             echo "      -SharedRuntime"
+            echo "  --skip-non-versioned-files     Skips non-versioned files if they already exist, such as the dotnet executable."
+            echo "      -SkipNonVersionedFiles"
             echo "  --dry-run,-DryRun              Do not perform installation. Display download link."
             echo "  --no-path, -NoPath             Do not set PATH for the current process."
             echo "  --verbose,-Verbose             Display diagnostics information."