Re: [PATCH] Bash snippet to show branch and patch in bash prompt

From: Eran Tromer <git2eran@tromer.org>
Date: Oct 30, 2006, 15:03 UTC
Message-ID: <45461429.4020108@tromer.org>
In-Reply-To: <20061030105926.14328.55180.stgit@lathund.dewire.com>

On 2006-10-30 12:59, Robin Rosenberg wrote:

> From: Robin Rosenberg <robin.rosenberg@dewire.com>

> +    function stgtag
> +    {
> +	git_dir=$(git-rev-parse --git-dir 2> /dev/null)
> +	ref=$(git-symbolic-ref HEAD 2> /dev/null)

Abort early if we're not in a git repo:
	git_dir=$(git-rev-parse --git-dir 2> /dev/null) || return
	ref=$(git-symbolic-ref HEAD 2> /dev/null) || return

> +	br=${ref/refs\/heads\//}

You want to strip a prefix only, so this is safer:
	br=${ref#refs/heads/}

> +	top=$(cat $git_dir/patches/$br/current 2>/dev/null)

All variables should be declared local to avoid polluting the bash variable namespace. Likewise, the function name deserves a couple of underscores.

> +	if [[ -n "$br$top" ]];then
> +	    echo "[$top@$br]"

It seems better to put the StGIT top after the tag, so that stg push/pop shifts less of the prompt, making it easier to see the change visually.

Corresponding modified version:

-------------------------------------------
if [ "$PS1" ]; then
    function __prompt_git()
    {
        local git_dir ref br top;
	git_dir=$(git-rev-parse --git-dir 2> /dev/null) || return
	ref=$(git-symbolic-ref HEAD 2> /dev/null) || return
	br=${ref#refs/heads/}
	top=$(cat $git_dir/patches/$br/current 2>/dev/null) \
		&& top="#$top"
	echo "[$br$top]"
    }
    PS1='\u@\h$(__prompt_git)\w\$ '
fi
-------------------------------------------

Conditionally prepending the "#" to $top can be done more concisely via ${top:+#$top} but I used the more readable version.