1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
|
.\" SPDX-FileCopyrightText: Peter Pentchev <roam@ringlet.net>
.\" SPDX-License-Identifier: BSD-2-Clause
.\"
.Dd April 21, 2018
.Dt FEATURE-CHECK 1
.Os
.Sh NAME
.Nm feature-check
.Nd query a program for supported features
.Sh SYNOPSIS
.Nm
.Op Fl v
.Op Fl O Ar optname
.Op Fl P Ar prefix
.Ar program
.Ar feature-name
.Nm
.Op Fl O Ar optname
.Op Fl P Ar prefix
.Ar program
.Ar feature-name
.Ar op
.Ar version
.Nm
.Op Fl O Ar optname
.Op Fl o Ar json|tsv
.Op Fl P Ar prefix
.Fl l
.Ar program
.Nm
.Fl V | Fl h
.Nm
.Fl -features
.Sh DESCRIPTION
The
.Nm
tool obtains the list of supported features from a program via various
methods (e.g. running it with the
.Fl -features
command-line option) and allows other programs to check for the presence
and, possibly, versions of specific features.
.Pp
Options:
.Bl -tag -width indent
.It Fl -features
List the compile-time features supported by this version of
.Nm :
.Bl -tag -width indent
.It Dv feature-check
Always present, with the version of the
.Nm
tool.
.It Dv list
Present if the
.Nm
tool supports fetching the list of features supported by a program.
.It Dv simple
Present if the
.Nm
tool supports comparing the version of a single feature against
a specified version string.
.It Dv single
Present if the
.Nm
tool supports querying a single feature.
.El
.It Fl h , Fl -help
Display program usage output and exit.
.It Fl O Ar optname
Specify the option to pass to the program to obtain its list of
features (default
.Fl -features ) .
.It Fl o Ar format
Specify the output format for the full list of features with the
.Fl l
option.
.It Fl P Ar prefix
Specify the prefix that
.Nm
should look for in the program's output to find the line that contains
the list of features; default "Features: ".
.It Fl V , Fl -version
Display program version output and exit.
.It Fl v
When querying a single feature, output the version obtained for it.
.El
.Sh EXIT STATUS
When querying a single feature,
.Nm
will exit with code 0 if the program supports that feature, and with
a non-zero code when either the program could not be executed, or
its list of features could not be parsed, or the feature was not present.
.Pp
When examining the version of a single feature,
.Nm
will exit with code 0 if the comparison result is true, and with
a non-zero code when either the program could not be executed, or
its list of features could not be parsed, or the comparison failed.
.Pp
When listing the features supported by a program,
.Nm
will exit with code 0 when the list of features was obtained and output,
and with a non-zero code when either the program could not be executed or
its list of features could not be parsed.
.Sh EXAMPLES
.Pp
The following examples are shown as given to the shell:
.Pp
.Dl feature-check curl AsynchDNS
.Pp
Exit with code 0 if the
.Xr curl 1
tool is present and it supports asynchronous DNS lookups.
.Pp
.Dl feature-check -l confget
.Pp
List the features supported by the
.Xr confget 1
tool.
.Pp
.Dl feature-check timelimit 'timelimit ge 1.9'
.Pp
Exit with code 0 if the
.Xr timelimit 1
tool advertises its
.Dv timelimit
feature at version 1.9 or later.
.Pp
.Dl feature-check timelimit timelimit ge 1.9
.Pp
The same check; note that the
.Nm
tool will treat all the arguments after the program name as a single
expression, i.e. it will concatenate them into a single string separated
by spaces and then interpret the string.
.Sh STANDARDS
No standards documentation was harmed in the process of creating
.Nm .
.Sh BUGS
Please report any bugs in
.Nm
to the author.
.Sh AUTHOR
The
.Nm
utility was written by
.An Peter Pentchev Aq roam@ringlet.net
in 2018.
|
