Updated gen_version script from GRSISort version of it

util/gen_version.sh

@@ -1,21 +1,22 @@
 #!/bin/bash
 
-if [ `uname` == 'Darwin' ]; then
-   script_dir=$(dirname $(greadlink -f "$0"))
+if [ "$(uname)" == "Darwin" ]; then
+   script_name=$(greadlink -f "$0")
 else
-   script_dir=$(dirname $(readlink -f "$0"))
+   script_name=$(readlink -f "$0")
 fi
+script_dir=$(dirname "$script_name")
 
 include_file="$script_dir"/../include/GRSIDataVersion.h
 
 release_commit=$(git describe --abbrev=0 --match="v*" --tags)
-release_num=$(echo "$release_commit" | sed -e 's/v//')
-release_time=$(git show -s --format=%ai "$release_commit" | tail -n 1)
+release_num=${release_commit//v/}
+release_time=$(git show -s --pretty=format:%ai "$release_commit" | tail -n 1)
 release_name=$(git rev-parse "$release_commit" | xargs git cat-file -p | tail -n1)
 
 git_commit=$(git describe --tags)
 git_branch=$(git branch | sed -n '/\* /s///p')
-git_commit_time=$(git show -s --format=%ai "$git_commit" | tail -n 1)
+git_commit_time=$(git show -s --pretty=format:%ai "$git_commit" | tail -n 1)
 
 read -r -d '' file_contents <<EOF
 #ifndef GRSIDATAVERSION_H