install.sh: Improve default $PREFIX behaviour

As before we default to /usr/local but now we switch to ~/.local if
/usr/local if not accessible instead of prompting for sudo. Instead
of having an exception for macOS/arm64.

Of course if a user wants to install in /usr/local anyway, they can
still pass --prefix /usr/local to force installation into /usr/local
and prompt for sudo.

ci/release/_build.sh

@@ -10,10 +10,11 @@ VERSION=$VERSION sh_c eval "'$HW_BUILD_DIR/README.md.sh'" \> "'$HW_BUILD_DIR/REA
 sh_c rm -f "$HW_BUILD_DIR/README.md.sh"
 sh_c find "$HW_BUILD_DIR" -exec touch {} \\\;
 
-export GOOS=$(goos "$OS")
+ensure_goos
-export GOARCH="$ARCH"
+ensure_goarch
 sh_c mkdir -p "$HW_BUILD_DIR/bin"
-sh_c go build -ldflags "'-X oss.terrastruct.com/d2/lib/version.Version=$VERSION'" \
+sh_c CGO_ENABLED=0 go build \
+  -ldflags "'-X oss.terrastruct.com/d2/lib/version.Version=$VERSION'" \
   -o "$HW_BUILD_DIR/bin/d2" .
 
 ARCHIVE=$PWD/$ARCHIVE

ci/release/_install.sh

@@ -14,7 +14,7 @@ help() {
   fi
 
   cat <<EOF
-usage: $arg0 [-d|--dry-run] [--version vX.X.X] [--edge] [--method detect] [--prefix /usr/local]
+usage: $arg0 [-d|--dry-run] [--version vX.X.X] [--edge] [--method detect] [--prefix path]
   [--tala latest] [--force] [--uninstall]
 
 install.sh automates the installation of D2 onto your system. It currently only supports
@@ -24,6 +24,9 @@ docs for --detect below for more information
 If you pass --edge, it will clone the source, build a release and install from it.
 --edge is incompatible with --tala and currently unimplemented.
 
+\$PREFIX in the docs below refers to the path set by --prefix. See docs on the --prefix
+flag below for the default.
+
 Flags:
 
 -d, --dry-run
@@ -51,30 +54,31 @@ Flags:
     So far it only detects macOS and automatically uses homebrew.
   - homebrew uses https://brew.sh/ which is a macOS and Linux package manager.
   - standalone installs a standalone release archive into the unix hierarchy path
-     specified by --prefix which defaults to /usr/local
+     specified by --prefix
-     Ensure /usr/local/bin is in your \$PATH to use it.
 
---prefix /usr/local
+--prefix path
   Controls the unix hierarchy path into which standalone releases are installed.
-  Defaults to /usr/local. You may also want to use ~/.local to avoid needing sudo.
+  Defaults to /usr/local or ~/.local if /usr/local is not writable by the current user.
-  We use ~/.local by default on arm64 macOS machines as SIP now disables access to
+  Remember that whatever you use, you must have the bin directory of your prefix path in
-  /usr/local. Remember that whatever you use, you must have the bin directory of your
+  \$PATH to execute the d2 binary. For example, if my prefix directory is /usr/local then
-  prefix path in \$PATH to execute the d2 binary. For example, if my prefix directory is
+  my \$PATH must contain /usr/local/bin.
-  /usr/local then my \$PATH must contain /usr/local/bin.
+  You may also need to include \$PREFIX/share/man into \$MANPATH.
+  install.sh will tell you whether \$PATH or \$MANPATH need to be updated after successful
+  installation.
 
 --tala [latest]
   Install Terrastruct's closed source TALA for improved layouts.
   See https://github.com/terrastruct/tala
   It optionally takes an argument of the TALA version to install.
   Installation obeys all other flags, just like the installation of d2. For example,
-  the d2plugin-tala binary will be installed into /usr/local/bin/d2plugin-tala
+  the d2plugin-tala binary will be installed into \$PREFIX/bin/d2plugin-tala
   warn: The version may not be obeyed with package manager installations. Use
         --method=standalone to enforce the version.
 
 --force:
   Force installation over the existing version even if they match. It will attempt a
   uninstall first before installing the new version. The installed release tree
-  will be deleted from /usr/local/lib/d2/d2-<VERSION> but the release archive in
+  will be deleted from \$PREFIX/lib/d2/d2-<VERSION> but the release archive in
   ~/.cache/d2/release will remain.
 
 --uninstall:
@@ -85,7 +89,7 @@ Flags:
   note: tala will also be uninstalled if installed.
 
 All downloaded archives are cached into ~/.cache/d2/release. use \$XDG_CACHE_HOME to change
-path of the cached assets. Release archives are unarchived into /usr/local/lib/d2/d2-<VERSION>
+path of the cached assets. Release archives are unarchived into \$PREFIX/lib/d2/d2-<VERSION>
 
 note: Deleting the unarchived releases will cause --uninstall to stop working.
 
@@ -150,13 +154,9 @@ main() {
   fi
 
   REPO=${REPO:-terrastruct/d2}
-  OS=$(os)
+  ensure_os
-  ARCH=$(arch)
+  ensure_arch
-  if [ -z "${PREFIX-}" -a "$OS" = macos -a "$ARCH" = arm64 ]; then
+  ensure_prefix
-    # M1 Mac's do not allow modifications to /usr/local even with sudo.
-    PREFIX=$HOME/.local
-  fi
-  PREFIX=${PREFIX:-/usr/local}
   CACHE_DIR=$(cache_dir)
   mkdir -p "$CACHE_DIR"
   METHOD=${METHOD:-detect}
@@ -318,11 +318,7 @@ install_d2_standalone() {
   asset_url=$(sh_c 'sed -n $((asset_line-3))p "$RELEASE_INFO" | sed "s/^.*: \"\(.*\)\",$/\1/g"')
   fetch_gh "$asset_url" "$CACHE_DIR/$ARCHIVE" 'application/octet-stream'
 
-  sh_c="sh_c"
+  ensure_prefix_sh_c
-  if ! is_prefix_writable; then
-    sh_c="sudo_sh_c"
-  fi
-
   "$sh_c" mkdir -p "'$INSTALL_DIR'"
   "$sh_c" tar -C "$INSTALL_DIR" -xzf "$CACHE_DIR/$ARCHIVE"
   "$sh_c" sh -c "'cd \"$INSTALL_DIR/d2-$VERSION\" && make install PREFIX=\"$PREFIX\"'"
@@ -365,11 +361,7 @@ install_tala_standalone() {
 
   fetch_gh "$asset_url" "$CACHE_DIR/$ARCHIVE" 'application/octet-stream'
 
-  sh_c="sh_c"
+  ensure_prefix_sh_c
-  if ! is_prefix_writable; then
-    sh_c="sudo_sh_c"
-  fi
-
   "$sh_c" mkdir -p "'$INSTALL_DIR'"
   "$sh_c" tar -C "$INSTALL_DIR" -xzf "$CACHE_DIR/$ARCHIVE"
   "$sh_c" sh -c "'cd \"$INSTALL_DIR/tala-$VERSION\" && make install PREFIX=\"$PREFIX\"'"
@@ -417,11 +409,7 @@ uninstall_d2_standalone() {
     return 1
   fi
 
-  sh_c="sh_c"
+  ensure_prefix_sh_c
-  if ! is_prefix_writable; then
-    sh_c="sudo_sh_c"
-  fi
-
   "$sh_c" sh -c "'cd \"$INSTALL_DIR/d2-$INSTALLED_VERSION\" && make uninstall PREFIX=\"$PREFIX\"'"
   "$sh_c" rm -rf "$INSTALL_DIR/d2-$INSTALLED_VERSION"
 }
@@ -439,11 +427,7 @@ uninstall_tala_standalone() {
     return 1
   fi
 
-  sh_c="sh_c"
+  ensure_prefix_sh_c
-  if ! is_prefix_writable; then
-    sh_c="sudo_sh_c"
-  fi
-
   "$sh_c" sh -c "'cd \"$INSTALL_DIR/tala-$INSTALLED_VERSION\" && make uninstall PREFIX=\"$PREFIX\"'"
   "$sh_c" rm -rf "$INSTALL_DIR/tala-$INSTALLED_VERSION"
 }
@@ -452,13 +436,6 @@ uninstall_tala_brew() {
   sh_c brew remove tala
 }
 
-is_prefix_writable() {
-  # The reason for checking whether $INSTALL_DIR is writable is that on macOS you have
-  # /usr/local owned by root but you don't need root to write to its subdirectories which
-  # is all we want to do.
-  is_writable_dir "$INSTALL_DIR"
-}
-
 cache_dir() {
   if [ -n "${XDG_CACHE_HOME-}" ]; then
     echo "$XDG_CACHE_HOME/d2/release"

ci/release/build.sh

@@ -109,11 +109,14 @@ main() {
   VERSION=${VERSION:-$(git_describe_ref)}
   BUILD_DIR=ci/release/build/$VERSION
   if [ -n "${HOST_ONLY-}" ]; then
-    runjob $(os)-$(arch) "OS=$(os) ARCH=$(arch) build"
+    OS=$(os)
+    ARCH=$(arch)
+    runjob "$OS-$ARCH" "build"
+
     if [ -n "${INSTALL-}" ]; then
-      ( sh_c make -sC "ci/release/build/$VERSION/$(os)-$(arch)/d2-$VERSION" install)
+      sh_c make -sC "ci/release/build/$VERSION/$(os)-$(arch)/d2-$VERSION" install
     elif [ -n "${UNINSTALL-}" ]; then
-      ( sh_c make -sC "ci/release/build/$VERSION/$(os)-$(arch)/d2-$VERSION" uninstall)
+      sh_c make -sC "ci/release/build/$VERSION/$(os)-$(arch)/d2-$VERSION" uninstall
     fi
     return 0
   fi
@@ -123,7 +126,7 @@ main() {
   runjob macos-amd64 'OS=macos ARCH=amd64 build' &
   runjob macos-arm64 'OS=macos ARCH=arm64 build' &
   runjob windows-amd64 'OS=windows ARCH=amd64 build' &
-  runjob windows-arm64 'OS=macos ARCH=arm64 build' &
+  runjob windows-arm64 'OS=windows ARCH=arm64 build' &
   waitjobs
 }
 
@@ -189,8 +192,7 @@ build_local() {
 
 build_remote_macos() {
   sh_c lockfile_ssh "$REMOTE_HOST" .d2-build-lock
-  sh_c ssh "$REMOTE_HOST" mkdir -p src
+  sh_c gitsync "$REMOTE_HOST" src/d2
-  sh_c rsync --archive --human-readable --delete ./ "$REMOTE_HOST:src/d2/"
   sh_c ssh "$REMOTE_HOST" "COLOR=${COLOR-} \
 TERM=${TERM-} \
 DRY_RUN=${DRY_RUN-} \
@@ -207,8 +209,7 @@ PATH=\\\"/usr/local/bin:/usr/local/sbin:/opt/homebrew/bin:/opt/homebrew/sbin\\\$
 
 build_remote_linux() {
   sh_c lockfile_ssh "$REMOTE_HOST" .d2-build-lock
-  sh_c ssh "$REMOTE_HOST" mkdir -p src
+  sh_c gitsync "$REMOTE_HOST" src/d2
-  sh_c rsync --archive --human-readable --delete ./ "$REMOTE_HOST:src/d2/"
   sh_c ssh "$REMOTE_HOST" "COLOR=${COLOR-} \
 TERM=${TERM-} \
 DRY_RUN=${DRY_RUN-} \

ci/release/builders/aws_ensure.sh

@@ -253,7 +253,7 @@ init_remote_macos() {
   sh_c ssh "$REMOTE_HOST" '"/bin/bash -c \"\$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)\""'
   sh_c ssh "$REMOTE_HOST" 'PATH="/usr/local/bin:/opt/homebrew/bin:\$PATH" brew update'
   sh_c ssh "$REMOTE_HOST" 'PATH="/usr/local/bin:/opt/homebrew/bin:\$PATH" brew upgrade'
-  sh_c ssh "$REMOTE_HOST" 'PATH="/usr/local/bin:/opt/homebrew/bin:\$PATH" brew install go'
+  sh_c ssh "$REMOTE_HOST" 'PATH="/usr/local/bin:/opt/homebrew/bin:\$PATH" brew install go rsync'
 }
 
 main "$@"

ci/release/changelogs/next.md

@@ -57,6 +57,11 @@ PRs when it's a visual change.
 - `d2` now lives in the root folder of the repository instead of as a subcommand. So you
   can now run `go install oss.terrastruct.com/d2@latest` to install from source.
   [#290](https://github.com/terrastruct/d2/pull/290)
+- `install.sh` defaults to installation to `/usr/local` as before but now if
+  `/usr/local` is not accessible to the current user, it will use `~/.local`
+  instead of prompting for sudo. You can pass `--prefix /usr/local` to force
+  installation into `/usr/local` with a prompt for sudo.
+  [#372](https://github.com/terrastruct/d2/pull/372)
 
 #### Bugfixes ⛑️
 

ci/release/template/Makefile

@@ -6,12 +6,10 @@ all:
 	( . ./scripts/lib.sh && echoerr "You must provide a target of install or uninstall for this Makefile" )
 	exit 1
 
-PREFIX = $(DESTDIR)/usr/local
-
 .PHONY: install
 install:
-	PREFIX='$(PREFIX)' ./scripts/install.sh
+	./scripts/install.sh
 
 .PHONY: uninstall
 uninstall:
-	PREFIX='$(PREFIX)' ./scripts/uninstall.sh
+	./scripts/uninstall.sh

ci/release/template/README.md.sh

@@ -13,16 +13,17 @@ version: $VERSION
 \`\`\`sh
 make install DRY_RUN=1
 # If it looks right, run:
-make install
+# make install
 \`\`\`
 
-Pass \`PREFIX=whatever\` to change the installation prefix.
+Pass \`PREFIX=somepath\` to change the installation prefix from the default which is
+\`/usr/local\` or \`~/.local\` if \`/usr/local\` is not writable with the current user.
 
 ## Uninstall
 
 \`\`\`sh
 make uninstall DRY_RUN=1
 # If it looks right, run:
-make uninstall
+# make uninstall
 \`\`\`
 EOF

ci/release/template/scripts/install.sh

@@ -4,16 +4,7 @@ cd -- "$(dirname "$0")/.."
 . ./scripts/lib.sh
 
 main() {
-  if [ -z "${PREFIX-}" ]; then
+  ensure_prefix_sh_c
-    echoerr "\$PREFIX must be set to a unix prefix directory in which to install d2 like /usr/local"
-    return 1
-  fi
-
-  sh_c="sh_c"
-  if ! is_writable_dir "$PREFIX/bin"; then
-    sh_c="sudo_sh_c"
-  fi
-
   "$sh_c" mkdir -p "$PREFIX/bin"
   "$sh_c" install ./bin/d2 "$PREFIX/bin/d2"
   "$sh_c" mkdir -p "$PREFIX/share/man/man1"

ci/release/template/scripts/lib.sh

@@ -23,11 +23,14 @@ pick() {
   shift
 
   seed_file="$(mktemp)"
-  echo "$seed" >"$seed_file"
+
-  # We add 16 more bytes to the seed file for sufficient entropy. Otherwise both Cygwin's
+  # We add 32 more bytes to the seed file for sufficient entropy. Otherwise both Cygwin's
   # and MinGW's sort for example complains about the lack of entropy on stderr and writes
   # nothing to stdout. I'm sure there are more platforms that would too.
-  echo "================" >"$seed_file"
+  #
+  # We also limit to a max of 32 bytes as otherwise macOS's sort complains that the random
+  # seed is too large. Probably more platforms too.
+  (echo "$seed" && echo "================================") | head -c32 >"$seed_file"
 
   while [ $# -gt 0 ]; do
     echo "$1"
@@ -89,16 +92,20 @@ _echo() {
   printf '%s\n' "$*"
 }
 
-  # 1-6 are regular and 9-14 are bright.
 get_rand_color() {
-  colors=""
+  if [ "${TERM_COLORS+x}" != x ]; then
-  ncolors=$(command tput colors)
+    TERM_COLORS=""
+    export TERM_COLORS
+    ncolors=$(TERM=${TERM:-xterm-256color} command tput colors)
     if [ "$ncolors" -ge 8 ]; then
-    colors="$colors 1 2 3 4 5 6"
+      # 1-6 are regular
+      TERM_COLORS="$TERM_COLORS 1 2 3 4 5 6"
     elif [ "$ncolors" -ge 16 ]; then
-    colors="$colors 9 10 11 12 13 14"
+      # 9-14 are bright.
+      TERM_COLORS="$TERM_COLORS 9 10 11 12 13 14"
     fi
-  pick "$*" $colors
+  fi
+  pick "$*" $TERM_COLORS
 }
 
 echop() {
@@ -117,14 +124,12 @@ printfp() {(
   prefix="$1"
   shift
 
-  if [ -z "${FGCOLOR-}" ]; then
+  _FGCOLOR=${FGCOLOR:-$(get_rand_color "$prefix")}
-    FGCOLOR="$(get_rand_color "$prefix")"
-  fi
   should_color || true
   if [ $# -eq 0 ]; then
-    printf '%s' "$(COLOR=$__COLOR setaf "$FGCOLOR" "$prefix")"
+    printf '%s' "$(COLOR=$__COLOR setaf "$_FGCOLOR" "$prefix")"
   else
-    printf '%s: %s\n' "$(COLOR=$__COLOR setaf "$FGCOLOR" "$prefix")" "$(printf "$@")"
+    printf '%s: %s\n' "$(COLOR=$__COLOR setaf "$_FGCOLOR" "$prefix")" "$(printf "$@")"
   fi
 )}
 
@@ -302,36 +307,60 @@ capcode() {
   code=$?
   set -e
 }
+
+strjoin() {
+  (IFS="$1"; shift; echo "$*")
+}
 #!/bin/sh
 if [ "${LIB_RELEASE-}" ]; then
   return 0
 fi
 LIB_RELEASE=1
 
-goos() {
+ensure_goos() {
-  case $1 in
+  if [ -n "${GOOS-}" ]; then
-    macos) echo darwin;;
+    return
-    *) echo $1;;
+  fi
+  ensure_os
+  case "$OS" in
+    macos) export GOOS=darwin;;
+    *) export GOOS=$1;;
   esac
 }
 
-os() {
+ensure_goarch() {
+  if [ -n "${GOARCH-}" ]; then
+    return
+  fi
+  ensure_arch
+  case "$ARCH" in
+    *) export GOARCH=$1;;
+  esac
+}
+
+ensure_os() {
+  if [ -n "${OS-}" ]; then
+    return
+  fi
   uname=$(uname)
   case $uname in
-    Linux) echo linux;;
+    Linux) OS=linux;;
-    Darwin) echo macos;;
+    Darwin) OS=macos;;
-    FreeBSD) echo freebsd;;
+    FreeBSD) OS=freebsd;;
-    CYGWIN_NT*|MINGW32_NT*) echo windows;;
+    CYGWIN_NT*|MINGW32_NT*) OS=windows;;
-    *) echo "$uname";;
+    *) OS=$uname;;
   esac
 }
 
-arch() {
+ensure_arch() {
+  if [ -n "${ARCH-}" ]; then
+    return
+  fi
   uname_m=$(uname -m)
   case $uname_m in
-    aarch64) echo arm64;;
+    aarch64) ARCH=arm64;;
-    x86_64) echo amd64;;
+    x86_64) ARCH=amd64;;
-    *) echo "$uname_m";;
+    *) ARCH=$uname_m;;
   esac
 }
 
@@ -350,9 +379,34 @@ manpath() {
 }
 
 is_writable_dir() {
-  # The path has to exist for -w to succeed.
+  # If it can be created, we can use it.
-  sh_c "mkdir -p '$1' 2>/dev/null" || true
+  sh_c "mkdir -p '$1' 2>/dev/null"
-  if [ ! -w "$1" ]; then
+}
-    return 1
+
+ensure_prefix() {
+  if [ -n "${PREFIX-}" ]; then
+    return
+  fi
+  # The reason for checking whether bin is writable is that on macOS you have /usr/local
+  # owned by root but you don't need root to write to its subdirectories which is all we
+  # need to do.
+  if ! is_writable_dir "/usr/local/bin"; then
+    # This also handles M1 Mac's which do not allow modifications to /usr/local even
+    # with sudo.
+    PREFIX=$HOME/.local
+  else
+    PREFIX=/usr/local
+  fi
+}
+
+ensure_prefix_sh_c() {
+  ensure_prefix
+
+  sh_c="sh_c"
+  # The reason for checking whether bin is writable is that on macOS you have /usr/local
+  # owned by root but you don't need root to write to its subdirectories which is all we
+  # need to do.
+  if ! is_writable_dir "$PREFIX/bin"; then
+    sh_c="sudo_sh_c"
   fi
 }

ci/release/template/scripts/uninstall.sh

@@ -4,16 +4,7 @@ cd -- "$(dirname "$0")/.."
 . ./scripts/lib.sh
 
 main() {
-  if [ -z "${PREFIX-}" ]; then
+  ensure_prefix_sh_c
-    echoerr "\$PREFIX must be set to a unix prefix directory from which to uninstall d2 like /usr/local"
-    return 1
-  fi
-
-  sh_c="sh_c"
-  if ! is_writable_dir "$PREFIX/bin"; then
-    sh_c="sudo_sh_c"
-  fi
-
   "$sh_c" rm -f "$PREFIX/bin/d2"
   "$sh_c" rm -f "$PREFIX/share/man/man1/d2.1"
 }

ci/sub

@@ -1 +1 @@
-Subproject commit ad50bf9f1e302bfb1a4d3c6bb821f90979083265
+Subproject commit 153c562ec591b7d32e265fabbd426a6b69e4fde8

docs/INSTALL.md

@@ -47,9 +47,9 @@ We're careful shell programmers and are aware of the many footguns of the Unix s
 script was written carefully and with detail. For example, it is not vulnerable to partial
 execution and the entire script runs with `set -eu` and very meticulous quoting.
 
-It follows the XDG standards, installs `d2` properly into a Unix hierarchy path (defaulting
+It follows the XDG standards, installs `d2` properly into a Unix hierarchy path
-to /usr/local though you can use ~/.local to avoid sudo if you'd like) and allows for easy
+(`/usr/local` unless `/usr/local` requires sudo in which case `~/.local` is used) and
-uninstall.
+allows for easy uninstall. You can easily adjust the used path with `--prefix`.
 
 Some other niceties are that it'll tell you if you need to adjust `$PATH` or `$MANPATH` to
 access `d2` and its manpages. It can also install
@@ -126,10 +126,6 @@ The install script places the standalone release into `$PREFIX/lib/d2/d2-<versio
 and we recommend doing the same with manually installed releases so that you
 know where the release directory is for easy uninstall.
 
-> warn: Our binary releases aren't fully static like normal Go binaries due to the C
-> dependency on v8go for executing dagre. If you're on an older system with an old
-> libc, you'll want to install from source.
-
 ## From source
 
 You can always install from source:

install.sh

@@ -28,11 +28,14 @@ pick() {
   shift
 
   seed_file="$(mktemp)"
-  echo "$seed" >"$seed_file"
+
-  # We add 16 more bytes to the seed file for sufficient entropy. Otherwise both Cygwin's
+  # We add 32 more bytes to the seed file for sufficient entropy. Otherwise both Cygwin's
   # and MinGW's sort for example complains about the lack of entropy on stderr and writes
   # nothing to stdout. I'm sure there are more platforms that would too.
-  echo "================" >"$seed_file"
+  #
+  # We also limit to a max of 32 bytes as otherwise macOS's sort complains that the random
+  # seed is too large. Probably more platforms too.
+  (echo "$seed" && echo "================================") | head -c32 >"$seed_file"
 
   while [ $# -gt 0 ]; do
     echo "$1"
@@ -94,16 +97,20 @@ _echo() {
   printf '%s\n' "$*"
 }
 
-  # 1-6 are regular and 9-14 are bright.
 get_rand_color() {
-  colors=""
+  if [ "${TERM_COLORS+x}" != x ]; then
-  ncolors=$(command tput colors)
+    TERM_COLORS=""
+    export TERM_COLORS
+    ncolors=$(TERM=${TERM:-xterm-256color} command tput colors)
     if [ "$ncolors" -ge 8 ]; then
-    colors="$colors 1 2 3 4 5 6"
+      # 1-6 are regular
+      TERM_COLORS="$TERM_COLORS 1 2 3 4 5 6"
     elif [ "$ncolors" -ge 16 ]; then
-    colors="$colors 9 10 11 12 13 14"
+      # 9-14 are bright.
+      TERM_COLORS="$TERM_COLORS 9 10 11 12 13 14"
     fi
-  pick "$*" $colors
+  fi
+  pick "$*" $TERM_COLORS
 }
 
 echop() {
@@ -122,14 +129,12 @@ printfp() {(
   prefix="$1"
   shift
 
-  if [ -z "${FGCOLOR-}" ]; then
+  _FGCOLOR=${FGCOLOR:-$(get_rand_color "$prefix")}
-    FGCOLOR="$(get_rand_color "$prefix")"
-  fi
   should_color || true
   if [ $# -eq 0 ]; then
-    printf '%s' "$(COLOR=$__COLOR setaf "$FGCOLOR" "$prefix")"
+    printf '%s' "$(COLOR=$__COLOR setaf "$_FGCOLOR" "$prefix")"
   else
-    printf '%s: %s\n' "$(COLOR=$__COLOR setaf "$FGCOLOR" "$prefix")" "$(printf "$@")"
+    printf '%s: %s\n' "$(COLOR=$__COLOR setaf "$_FGCOLOR" "$prefix")" "$(printf "$@")"
   fi
 )}
 
@@ -307,6 +312,10 @@ capcode() {
   code=$?
   set -e
 }
+
+strjoin() {
+  (IFS="$1"; shift; echo "$*")
+}
 #!/bin/sh
 if [ "${LIB_FLAG-}" ]; then
   return 0
@@ -444,30 +453,50 @@ if [ "${LIB_RELEASE-}" ]; then
 fi
 LIB_RELEASE=1
 
-goos() {
+ensure_goos() {
-  case $1 in
+  if [ -n "${GOOS-}" ]; then
-    macos) echo darwin;;
+    return
-    *) echo $1;;
+  fi
+  ensure_os
+  case "$OS" in
+    macos) export GOOS=darwin;;
+    *) export GOOS=$1;;
   esac
 }
 
-os() {
+ensure_goarch() {
+  if [ -n "${GOARCH-}" ]; then
+    return
+  fi
+  ensure_arch
+  case "$ARCH" in
+    *) export GOARCH=$1;;
+  esac
+}
+
+ensure_os() {
+  if [ -n "${OS-}" ]; then
+    return
+  fi
   uname=$(uname)
   case $uname in
-    Linux) echo linux;;
+    Linux) OS=linux;;
-    Darwin) echo macos;;
+    Darwin) OS=macos;;
-    FreeBSD) echo freebsd;;
+    FreeBSD) OS=freebsd;;
-    CYGWIN_NT*|MINGW32_NT*) echo windows;;
+    CYGWIN_NT*|MINGW32_NT*) OS=windows;;
-    *) echo "$uname";;
+    *) OS=$uname;;
   esac
 }
 
-arch() {
+ensure_arch() {
+  if [ -n "${ARCH-}" ]; then
+    return
+  fi
   uname_m=$(uname -m)
   case $uname_m in
-    aarch64) echo arm64;;
+    aarch64) ARCH=arm64;;
-    x86_64) echo amd64;;
+    x86_64) ARCH=amd64;;
-    *) echo "$uname_m";;
+    *) ARCH=$uname_m;;
   esac
 }
 
@@ -486,10 +515,35 @@ manpath() {
 }
 
 is_writable_dir() {
-  # The path has to exist for -w to succeed.
+  # If it can be created, we can use it.
-  sh_c "mkdir -p '$1' 2>/dev/null" || true
+  sh_c "mkdir -p '$1' 2>/dev/null"
-  if [ ! -w "$1" ]; then
+}
-    return 1
+
+ensure_prefix() {
+  if [ -n "${PREFIX-}" ]; then
+    return
+  fi
+  # The reason for checking whether bin is writable is that on macOS you have /usr/local
+  # owned by root but you don't need root to write to its subdirectories which is all we
+  # need to do.
+  if ! is_writable_dir "/usr/local/bin"; then
+    # This also handles M1 Mac's which do not allow modifications to /usr/local even
+    # with sudo.
+    PREFIX=$HOME/.local
+  else
+    PREFIX=/usr/local
+  fi
+}
+
+ensure_prefix_sh_c() {
+  ensure_prefix
+
+  sh_c="sh_c"
+  # The reason for checking whether bin is writable is that on macOS you have /usr/local
+  # owned by root but you don't need root to write to its subdirectories which is all we
+  # need to do.
+  if ! is_writable_dir "$PREFIX/bin"; then
+    sh_c="sudo_sh_c"
   fi
 }
 #!/bin/sh
@@ -503,7 +557,7 @@ help() {
   fi
 
   cat <<EOF
-usage: $arg0 [-d|--dry-run] [--version vX.X.X] [--edge] [--method detect] [--prefix /usr/local]
+usage: $arg0 [-d|--dry-run] [--version vX.X.X] [--edge] [--method detect] [--prefix path]
   [--tala latest] [--force] [--uninstall]
 
 install.sh automates the installation of D2 onto your system. It currently only supports
@@ -513,6 +567,9 @@ docs for --detect below for more information
 If you pass --edge, it will clone the source, build a release and install from it.
 --edge is incompatible with --tala and currently unimplemented.
 
+\$PREFIX in the docs below refers to the path set by --prefix. See docs on the --prefix
+flag below for the default.
+
 Flags:
 
 -d, --dry-run
@@ -540,30 +597,31 @@ Flags:
     So far it only detects macOS and automatically uses homebrew.
   - homebrew uses https://brew.sh/ which is a macOS and Linux package manager.
   - standalone installs a standalone release archive into the unix hierarchy path
-     specified by --prefix which defaults to /usr/local
+     specified by --prefix
-     Ensure /usr/local/bin is in your \$PATH to use it.
 
---prefix /usr/local
+--prefix path
   Controls the unix hierarchy path into which standalone releases are installed.
-  Defaults to /usr/local. You may also want to use ~/.local to avoid needing sudo.
+  Defaults to /usr/local or ~/.local if /usr/local is not writable by the current user.
-  We use ~/.local by default on arm64 macOS machines as SIP now disables access to
+  Remember that whatever you use, you must have the bin directory of your prefix path in
-  /usr/local. Remember that whatever you use, you must have the bin directory of your
+  \$PATH to execute the d2 binary. For example, if my prefix directory is /usr/local then
-  prefix path in \$PATH to execute the d2 binary. For example, if my prefix directory is
+  my \$PATH must contain /usr/local/bin.
-  /usr/local then my \$PATH must contain /usr/local/bin.
+  You may also need to include \$PREFIX/share/man into \$MANPATH.
+  install.sh will tell you whether \$PATH or \$MANPATH need to be updated after successful
+  installation.
 
 --tala [latest]
   Install Terrastruct's closed source TALA for improved layouts.
   See https://github.com/terrastruct/tala
   It optionally takes an argument of the TALA version to install.
   Installation obeys all other flags, just like the installation of d2. For example,
-  the d2plugin-tala binary will be installed into /usr/local/bin/d2plugin-tala
+  the d2plugin-tala binary will be installed into \$PREFIX/bin/d2plugin-tala
   warn: The version may not be obeyed with package manager installations. Use
         --method=standalone to enforce the version.
 
 --force:
   Force installation over the existing version even if they match. It will attempt a
   uninstall first before installing the new version. The installed release tree
-  will be deleted from /usr/local/lib/d2/d2-<VERSION> but the release archive in
+  will be deleted from \$PREFIX/lib/d2/d2-<VERSION> but the release archive in
   ~/.cache/d2/release will remain.
 
 --uninstall:
@@ -574,7 +632,7 @@ Flags:
   note: tala will also be uninstalled if installed.
 
 All downloaded archives are cached into ~/.cache/d2/release. use \$XDG_CACHE_HOME to change
-path of the cached assets. Release archives are unarchived into /usr/local/lib/d2/d2-<VERSION>
+path of the cached assets. Release archives are unarchived into \$PREFIX/lib/d2/d2-<VERSION>
 
 note: Deleting the unarchived releases will cause --uninstall to stop working.
 
@@ -639,13 +697,9 @@ main() {
   fi
 
   REPO=${REPO:-terrastruct/d2}
-  OS=$(os)
+  ensure_os
-  ARCH=$(arch)
+  ensure_arch
-  if [ -z "${PREFIX-}" -a "$OS" = macos -a "$ARCH" = arm64 ]; then
+  ensure_prefix
-    # M1 Mac's do not allow modifications to /usr/local even with sudo.
-    PREFIX=$HOME/.local
-  fi
-  PREFIX=${PREFIX:-/usr/local}
   CACHE_DIR=$(cache_dir)
   mkdir -p "$CACHE_DIR"
   METHOD=${METHOD:-detect}
@@ -807,11 +861,7 @@ install_d2_standalone() {
   asset_url=$(sh_c 'sed -n $((asset_line-3))p "$RELEASE_INFO" | sed "s/^.*: \"\(.*\)\",$/\1/g"')
   fetch_gh "$asset_url" "$CACHE_DIR/$ARCHIVE" 'application/octet-stream'
 
-  sh_c="sh_c"
+  ensure_prefix_sh_c
-  if ! is_prefix_writable; then
-    sh_c="sudo_sh_c"
-  fi
-
   "$sh_c" mkdir -p "'$INSTALL_DIR'"
   "$sh_c" tar -C "$INSTALL_DIR" -xzf "$CACHE_DIR/$ARCHIVE"
   "$sh_c" sh -c "'cd \"$INSTALL_DIR/d2-$VERSION\" && make install PREFIX=\"$PREFIX\"'"
@@ -854,11 +904,7 @@ install_tala_standalone() {
 
   fetch_gh "$asset_url" "$CACHE_DIR/$ARCHIVE" 'application/octet-stream'
 
-  sh_c="sh_c"
+  ensure_prefix_sh_c
-  if ! is_prefix_writable; then
-    sh_c="sudo_sh_c"
-  fi
-
   "$sh_c" mkdir -p "'$INSTALL_DIR'"
   "$sh_c" tar -C "$INSTALL_DIR" -xzf "$CACHE_DIR/$ARCHIVE"
   "$sh_c" sh -c "'cd \"$INSTALL_DIR/tala-$VERSION\" && make install PREFIX=\"$PREFIX\"'"
@@ -906,11 +952,7 @@ uninstall_d2_standalone() {
     return 1
   fi
 
-  sh_c="sh_c"
+  ensure_prefix_sh_c
-  if ! is_prefix_writable; then
-    sh_c="sudo_sh_c"
-  fi
-
   "$sh_c" sh -c "'cd \"$INSTALL_DIR/d2-$INSTALLED_VERSION\" && make uninstall PREFIX=\"$PREFIX\"'"
   "$sh_c" rm -rf "$INSTALL_DIR/d2-$INSTALLED_VERSION"
 }
@@ -928,11 +970,7 @@ uninstall_tala_standalone() {
     return 1
   fi
 
-  sh_c="sh_c"
+  ensure_prefix_sh_c
-  if ! is_prefix_writable; then
-    sh_c="sudo_sh_c"
-  fi
-
   "$sh_c" sh -c "'cd \"$INSTALL_DIR/tala-$INSTALLED_VERSION\" && make uninstall PREFIX=\"$PREFIX\"'"
   "$sh_c" rm -rf "$INSTALL_DIR/tala-$INSTALLED_VERSION"
 }
@@ -941,13 +979,6 @@ uninstall_tala_brew() {
   sh_c brew remove tala
 }
 
-is_prefix_writable() {
-  # The reason for checking whether $INSTALL_DIR is writable is that on macOS you have
-  # /usr/local owned by root but you don't need root to write to its subdirectories which
-  # is all we want to do.
-  is_writable_dir "$INSTALL_DIR"
-}
-
 cache_dir() {
   if [ -n "${XDG_CACHE_HOME-}" ]; then
     echo "$XDG_CACHE_HOME/d2/release"