Git check file contents across branches - bash

Question

I'm currently using the following two bash functions to chunk through our git repo to determine what the latest version number is on each branch. Since we have several git hooks, including post-checkout, the gitTrackAll function can take quite a while to run. Is there any way to do what I'm doing without checking out every branch, pulling it in, then running a git show?
To clarify, I'm currently checking out each branch and getting the contents of the VERSION file. This essentially tells me what the last version that was merged into that branch is. We occasionally have some branches that stagnate while the developer is working on them. This list provides us a quick way to see what's way behind.
gitTrackAll && gitBranchVersions
function gitTrackAll(){
remote='origin';
for brname in `git branch -r | grep $remote | grep -v master | grep -v HEAD| awk '{gsub(/^[^\/]+\//,"",$1); print $1}'`; do
git checkout "$brname"
git branch --set-upstream-to $remote/$brname $brname;
git pull
done
git checkout master
}
function gitBranchVersions(){
line='--------------------------------------------------------------------------------'
line="$line$line"
for branch in $(git for-each-ref --format='%(refname)' refs/heads/); do
VER=$(git show "$branch":VERSION);
printf "%s %s $VER\n" $branch "${line:${#branch}}"
done
}
The resulting output looks a little like the following (branch names changed)
refs/heads/1954-branch-a ---------------------------------------------------------------------------------------------------------------------------------------- 2.9.27
refs/heads/1955-branch-b ---------------------------------------------------------------------------------------------------------------------------------------- 2.9.43
refs/heads/1965-branch-c ---------------------------------------------------------------------------------------------------------------------------------------- 2.9.32
refs/heads/1968-branch-d ---------------------------------------------------------------------------------------------------------------------------------------- 2.9.101
refs/heads/1969-branch-e ---------------------------------------------------------------------------------------------------------------------------------------- 2.9.114
refs/heads/master ----------------------------------------------------------------------------------------------------------------------------------------------- 2.9.115

Answer 1

I would rewrite gitTrackAll the following way without any checkout at all:
function gitTrackAll(){
remote='origin';
for brname in `git branch -r | grep $remote | grep -v master | grep -v HEAD| awk '{gsub(/^[^\/]+\//,"",$1); print $1}'`; do
git branch --set-upstream-to $remote/$brname $brname;
# git fetch cannot update the current branch - use git pull
git fetch $remote $brname:$brname || git pull $remote $brname
done
}

Answer 2

It looks like I can read files straight from remote. Using pieces from both functions, I've come up with the following, which works perfectly for the application I need.
function gitBranchVersions(){
line='--------------------------------------------------------------------------------'
line="$line$line"
remote='origin' ;
git fetch --all --prune
for brname in `git branch -r | grep $remote | grep -v HEAD| awk '{gsub(/^[^\/]+\//,"",$1); print $1}'`; do
VER=$(git show "$remote/$brname":VERSION);
printf "%s %s $VER\n" $brname "${line:${#brname}}"
done
}