git-for-each-ref.txt

git-for-each-ref(1)
===================

NAME
----
git-for-each-ref - Output information on each ref

SYNOPSIS
--------
[verse]
'git-for-each-ref' [--count=<count>]\*
 [--shell|--perl|--python|--tcl]
 [--sort=<key>]\* [--format=<format>] [<pattern>]

DESCRIPTION
-----------

Iterate over all refs that match `<pattern>` and show them
according to the given `<format>`, after sorting them according
to the given set of `<key>`. If `<max>` is given, stop after
showing that many refs. The interpolated values in `<format>`
can optionally be quoted as string literals in the specified
host language allowing their direct evaluation in that language.

OPTIONS
-------
<count>::
By default the command shows all refs that match
`<pattern>`. This option makes it stop after showing
that many refs.

<key>::
A field name to sort on. Prefix `-` to sort in
descending order of the value. When unspecified,
`refname` is used. More than one sort keys can be
given.

<format>::
A string that interpolates `%(fieldname)` from the
object pointed at by a ref being shown. If `fieldname`
is prefixed with an asterisk (`*`) and the ref points
at a tag object, the value for the field in the object
tag refers is used. When unspecified, defaults to
`%(objectname) SPC %(objecttype) TAB %(refname)`.
It also interpolates `%%` to `%`, and `%xx` where `xx`
are hex digits interpolates to character with hex code
`xx`; for example `%00` interpolates to `\0` (NUL),
`%09` to `\t` (TAB) and `%0a` to `\n` (LF).

<pattern>::
If given, the name of the ref is matched against this
using fnmatch(3). Refs that do not match the pattern
are not shown.

--shell, --perl, --python, --tcl::
If given, strings that substitute `%(fieldname)`
placeholders are quoted as string literals suitable for
the specified host language. This is meant to produce
a scriptlet that can directly be `eval`ed.


FIELD NAMES
-----------

Various values from structured fields in referenced objects can
be used to interpolate into the resulting output, or as sort
keys.

For all objects, the following names can be used:

refname::
The name of the ref (the part after $GIT_DIR/).

objecttype::
The type of the object (`blob`, `tree`, `commit`, `tag`).

objectsize::
The size of the object (the same as `git-cat-file -s` reports).

objectname::
The object name (aka SHA-1).

In addition to the above, for commit and tag objects, the header
field names (`tree`, `parent`, `object`, `type`, and `tag`) can
be used to specify the value in the header field.

Fields that have name-email-date tuple as its value (`author`,
`committer`, and `tagger`) can be suffixed with `name`, `email`,
and `date` to extract the named component.

The first line of the message in a commit and tag object is
`subject`, the remaining lines are `body`. The whole message
is `contents`.

For sorting purposes, fields with numeric values sort in numeric
order (`objectsize`, `authordate`, `committerdate`, `taggerdate`).
All other fields are used to sort in their byte-value order.

In any case, a field name that refers to a field inapplicable to
the object referred by the ref does not cause an error. It
returns an empty string instead.


EXAMPLES
--------

An example directly producing formatted text. Show the most recent
3 tagged commits::

------------
#!/bin/sh

git-for-each-ref --count=3 --sort='-*authordate' \
--format='From: %(*authorname) %(*authoremail)
Subject: %(*subject)
Date: %(*authordate)
Ref: %(*refname)

%(*body)
' 'refs/tags'
------------


A simple example showing the use of shell eval on the output,
demonstrating the use of --shell. List the prefixes of all heads::
------------
#!/bin/sh

git-for-each-ref --shell --format="ref=%(refname)" refs/heads | \
while read entry
do
eval "$entry"
echo `dirname $ref`
done
------------


A bit more elaborate report on tags, demonstrating that the format
may be an entire script::
------------
#!/bin/sh

fmt='
r=%(refname)
t=%(*objecttype)
T=${r#refs/tags/}

o=%(*objectname)
n=%(*authorname)
e=%(*authoremail)
s=%(*subject)
d=%(*authordate)
b=%(*body)

kind=Tag
if test "z$t" = z
then
# could be a lightweight tag
t=%(objecttype)
kind="Lightweight tag"
o=%(objectname)
n=%(authorname)
e=%(authoremail)
s=%(subject)
d=%(authordate)
b=%(body)
fi
echo "$kind $T points at a $t object $o"
if test "z$t" = zcommit
then
echo "The commit was authored by $n $e
at $d, and titled

 $s

Its message reads as:
"
echo "$b" | sed -e "s/^/ /"
echo
fi
'

eval=`git-for-each-ref --shell --format="$fmt" \
--sort='*objecttype' \
--sort=-taggerdate \
refs/tags`
eval "$eval"
------------