Add git-for-each-ref: helper for language bindings
[git/git.git] / Documentation / git-for-each-ref.txt
1 git-for-each-ref(1)
2 ===================
3
4 NAME
5 ----
6 git-for-each-ref - Output information on each ref
7
8 SYNOPSIS
9 --------
10 'git-for-each-ref' [--count=<count>]* [--shell|--perl|--python] [--sort=<key>]* [--format=<format>] [<pattern>]
11
12 DESCRIPTION
13 -----------
14
15 Iterate over all refs that match `<pattern>` and show them
16 according to the given `<format>`, after sorting them according
17 to the given set of `<key>`s. If `<max>` is given, stop after
18 showing that many refs. The interporated values in `<format>`
19 can optionally be quoted as string literals in the specified
20 host language.
21
22 OPTIONS
23 -------
24 <count>::
25 By default the command shows all refs that match
26 `<pattern>`. This option makes it stop after showing
27 that many refs.
28
29 <key>::
30 A field name to sort on. Prefix `-` to sort in
31 descending order of the value. When unspecified,
32 `refname` is used. More than one sort keys can be
33 given.
34
35 <format>::
36 A string that interpolates `%(fieldname)` from the
37 object pointed at by a ref being shown. If `fieldname`
38 is prefixed with an asterisk (`*`) and the ref points
39 at a tag object, the value for the field in the object
40 tag refers is used. When unspecified, defaults to
41 `%(refname)`.
42
43 <pattern>::
44 If given, the name of the ref is matched against this
45 using fnmatch(3). Refs that do not match the pattern
46 are not shown.
47
48 --shell, --perl, --python::
49 If given, strings that substitute `%(fieldname)`
50 placeholders are quoted as string literals suitable for
51 the specified host language. This is meant to produce
52 a scriptlet that can directly be `eval`ed.
53
54
55 FIELD NAMES
56 -----------
57
58 Various values from structured fields in referenced objects can
59 be used to interpolate into the resulting output, or as sort
60 keys.
61
62 For all objects, the following names can be used:
63
64 refname::
65 The name of the ref (the part after $GIT_DIR/refs/).
66
67 objecttype::
68 The type of the object (`blob`, `tree`, `commit`, `tag`).
69
70 objectsize::
71 The size of the object (the same as `git-cat-file -s` reports).
72
73 objectname::
74 The object name (aka SHA-1).
75
76 In addition to the above, for commit and tag objects, the header
77 field names (`tree`, `parent`, `object`, `type`, and `tag`) can
78 be used to specify the value in the header field.
79
80 Fields that have name-email-date tuple as its value (`author`,
81 `committer`, and `tagger`) can be suffixed with `name`, `email`,
82 and `date` to extract the named component.
83
84 The first line of the message in a commit and tag object is
85 `subject`, the remaining lines are `body`. The whole message
86 is `contents`.
87
88 For sorting purposes, fields with numeric values sort in numeric
89 order (`objectsize`, `authordate`, `committerdate`, `taggerdate`).
90 All other fields are used to sort in their byte-value order.
91
92 In any case, a field name that refers to a field inapplicable to
93 the object referred by the ref does not cause an error. It
94 returns an empty string instead.
95
96
97 EXAMPLES
98 --------
99
100 Show the most recent 3 tagged commits::
101
102 ------------
103 #!/bin/sh
104
105 git-for-each-ref --count=3 --sort='-*authordate' \
106 --format='From: %(*authorname) %(*authoremail)
107 Subject: %(*subject)
108 Date: %(*authordate)
109 Ref: %(*refname)
110
111 %(*body)
112 ' 'refs/tags'
113 ------------
114
115 A bit more elaborate report on tags::
116 ------------
117 #!/bin/sh
118
119 fmt='
120 r=%(refname)
121 t=%(*objecttype)
122 T=${r#refs/tags/}
123
124 o=%(*objectname)
125 n=%(*authorname)
126 e=%(*authoremail)
127 s=%(*subject)
128 d=%(*authordate)
129 b=%(*body)
130
131 kind=Tag
132 if test "z$t" = z
133 then
134 # could be a lightweight tag
135 t=%(objecttype)
136 kind="Lightweight tag"
137 o=%(objectname)
138 n=%(authorname)
139 e=%(authoremail)
140 s=%(subject)
141 d=%(authordate)
142 b=%(body)
143 fi
144 echo "$kind $T points at a $t object $o"
145 if test "z$t" = zcommit
146 then
147 echo "The commit was authored by $n $e
148 at $d, and titled
149
150 $s
151
152 Its message reads as:
153 "
154 echo "$b" | sed -e "s/^/ /"
155 echo
156 fi
157 '
158
159 eval=`git-for-each-ref -s --format="$fmt" \
160 --sort='*objecttype' \
161 --sort=-taggerdate \
162 refs/tags`
163 eval "$eval"
164 ------------