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
|
Coding Style
============
C programs
----------
- Use C99 without GNU extensions. We compile with -std=gnu99 to support
list.h, but otherwise stay clear of GNU tricks.
- Kernel coding style (https://www.kernel.org/doc/Documentation/CodingStyle)
applies with the following exceptions:
- Points which are kernel specific (e.g. kmalloc)
- Lines can be up to 120 characters (although 80 is better)
- Use scripts/checkpatch-wrapper.sh to check code.
Shell scripts
-------------
- Use tabs for indentation
- Write <, >, <<, >> with space before, but no space after. E.g.
cat <<EOF >"${file}"
- Use $( ) instead of ``
- Use ${ } for variables
- Use 'type <command>' to check if command is installed
- Write "if", "for" and "while" structures with "then"/"do" on the next line
(not with semicolon on the same line). E.g.
if test -f foo.sh
then
do something
fi
for i in a b c
do
echo ${i}
done
- For short constructs, it is okay to use use && and || instead of
if-statements. E.g:
test -e foo || die "cannot find foo"
type special_command || die "cannot find program `special_command`"
- Use ./* rather than ls/$(ls) for lor loops
for i in ./*
do
echo $i
done
- Use "test" instead of [ ] or [[ ]] E.g.
test -n "${x}" && test "${a}" = "${b}"
- Use $(( )) to perform maths operations instead of "let" or "expr". E.g:
: $(( a += 5))
- Write functions like this
my_function () {
some code
}
- Quote variables except in for-loops and in $(( ))
### Stay POSIX friendly:
- Don't use bash specific features such as arrays and [[ ]]
- Avoid non-POSIX re-directions such as '&>', '>&-', '|&', etc
For example, to re-direct both stdout and stderr to /dev/null, do:
command >/dev/null 2>&1
- Don't use echo -e "foo", instead use
printf "%b\n" "foo"
- Don't use sed -i, it is not POSIX
- Don't use curly brace globbing such as "ls *.{c,h}"
|
