git glp # with no args will show unpushed changs

gistfile1.bash

#!/bin/bash
function git_current_tracking
{
    local BRANCH="$(git describe --contains --all HEAD)"
    local REMOTE="$(git config branch.$BRANCH.remote)"
    local MERGE="$(git config branch.$BRANCH.merge)"
    if [ -n "$REMOTE" -a -n "$MERGE" ]
    then
        echo "$REMOTE/$(echo "$MERGE" | sed 's#^refs/heads/##')"
    else
        echo "\"$BRANCH\" is not a tracking branch." >&2
        return 1
    fi
}

# don't use the pager if in word-diff mode
pager="$(echo "$*" | grep -q -- '--word-diff' && echo --no-pager)"

# use reverse mode if we have a range
reverse="$(echo "$*" | grep -q '\.\.' && echo --reverse)"

# if we have no non-option args then default to listing unpushed commits in reverse moode
if ! (for ARG in "$@"; do echo "$ARG" | grep -v '^-'; done) | grep -q . && git_current_tracking > /dev/null 2>&1
then
    default_range="$(git_current_tracking)..HEAD"
    reverse='--reverse'
else
    default_range=''
fi

git $pager slog $reverse "$@" $default_range