support FreeBSD (#260)

* start FreeBSD support

* permissions change

* improve command to fetch permissions.

* note we use 'shasum' and not 'sha256sum' on osx and freebsd

README.md

@@ -36,7 +36,7 @@ See the [installation section](http://git-secret.io/installation) for the detail
 - `gawk` since `4.0.2`
 - `git` since `1.8.3.1`
 - `gpg` since `gnupg 1.4` to `gnupg 2.X`
-- `sha256sum` since `8.21`
+- `sha256sum` since `8.21` (on freebsd and OSX `shasum` is used instead)
 
 
 ## Contributing

src/_utils/_git_secret_tools.sh

@@ -120,6 +120,10 @@ function _os_based {
       "$1_linux" "${@:2}"
     ;;
 
+    FreeBSD)
+      "$1_freebsd" "${@:2}"
+    ;;
+
     # TODO: add MS Windows support.
     # CYGWIN*|MINGW32*|MSYS*)
     #   $1_ms ${@:2}

src/_utils/_git_secret_tools_freebsd.sh

@@ -0,0 +1,37 @@
+#!/usr/bin/env bash
+
+# support for freebsd. Mostly the same as OSX.
+
+
+# shellcheck disable=1117
+function __replace_in_file_freebsd {
+  sed -i.bak "s/^\($1[[:space:]]*=[[:space:]]*\).*\$/\1$2/" "$3"
+}
+
+
+function __temp_file_freebsd {
+  : "${TMPDIR:=/tmp}"
+  local filename
+  filename=$(mktemp -t _gitsecrets_XXX )
+  echo "$filename";
+}
+
+
+function __sha256_freebsd {
+  # this is in a different location than osx
+  /usr/local/bin/shasum -a256 "$1"
+}
+
+function __get_octal_perms_freebsd {
+  local filename
+  filename=$1
+  local perms
+  perms=$(stat -f "%04OLp" "$filename")
+  # perms is a string like '0644'. 
+  # In the "%04OLp':
+  #   the '04' means 4 digits, 0 padded.  So we get 0644, not 644.
+  #   the 'O' means Octal.
+  #   the 'Lp' means 'low subfield of file type and permissions (st_mode).'
+  #     (without 'L' you get 6 digits like '100644'.)
+  echo "$perms"
+}

src/_utils/_git_secret_tools_linux.sh

@@ -22,5 +22,6 @@ function __get_octal_perms_linux {
   filename=$1
   local perms
   perms=$(stat --format '%a' "$filename")
+  # a string like '0644'
   echo "$perms"
 }

src/_utils/_git_secret_tools_osx.sh

@@ -18,10 +18,12 @@ function __temp_file_osx {
 function __sha256_osx {
   /usr/bin/shasum -a256 "$1"
 }
+
 function __get_octal_perms_osx {
   local filename
   filename=$1
   local perms
-  perms=$(stat -f '%p' "$filename")
+  perms=$(stat -f "%04OLp" "$filename")
+  # see _git_secret_tools_freebsd.sh for more about stat's format string
   echo "$perms"
 }