git-check-branch

#!/bin/bash -e
## Check if we're on a remote tracking branch

## read input, display help if necessary
if [[ "$@" == *--help* ]]; then
    cat<<EOF
 Check for a remote tracking branch

 This command checks whether the repository is on a remote tracking
 branch. Otherwise an error is raised.
 Does not raise an error if the repository is in detached HEAD mode 
 and there are no new commits.

 Usage:
    git check-branch
EOF
    exit 0;
fi

if !(git symbolic-ref -q HEAD > /dev/null) ; then
    ## detached head cannot be remote tracking branch...
    ## ...but: if there are no new commits, we can safely ignore this
    ## FIXME: this test only succeed if the new commit is actually
    ##        checked out
    if !(git diff origin... --quiet) ; then
	cat >&2 <<EOF
Error in $PWD:
 Detached head and new commits. Attach the HEAD by creating
 a new branch or risk losing the commits.
EOF
	exit 1
    fi
cat >&2 <<EOF
Warning in $PWD:
 Detached head. This probably just mean that there are updates available
 that are not yet used. To update to the most recent version, use 
   git attach-head -w
EOF
    exit 0
fi

## from the git mailinglist:
function git
{
    LC_MESSAGES=C command git "$@"
} 
export git

tmp=`git branch --no-color -vv 2> /dev/null`
while read line; do
    if [[ "${line:0:1}" != "*" ]]; then
	continue
    fi
    #echo "$line"
    remote=`expr "$line" : '.*\[\(.*\)\]'` || nontracking=0
done <<< "$tmp"

activebranch=`git name-rev --name-only HEAD`

if [[ "$nontracking" ]]; then
    ## if we're here: fail
    cat >&2 <<EOF 
Error in $PWD: 
 Branch "$activebranch" is not a remote tracking branch.
EOF
    exit 1
fi