- We use tabs for indentation.
- - Case arms are indented at the same depth as case and esac lines.
+ - Case arms are indented at the same depth as case and esac lines,
+ like this:
+
+ case "$variable" in
+ pattern1)
+ do this
+ ;;
+ pattern2)
+ do that
+ ;;
+ esac
- Redirection operators should be written with space before, but no
space after them. In other words, write 'echo test >"$file"'
redirection target in a variable (as shown above), our code does so
because some versions of bash issue a warning without the quotes.
+ (incorrect)
+ cat hello > world < universe
+ echo hello >$world
+
+ (correct)
+ cat hello >world <universe
+ echo hello >"$world"
+
- We prefer $( ... ) for command substitution; unlike ``, it
properly nests. It should have been the way Bourne spelled
it from day one, but unfortunately isn't.
"then" should be on the next line for if statements, and "do"
should be on the next line for "while" and "for".
+ (incorrect)
+ if test -f hello; then
+ do this
+ fi
+
+ (correct)
+ if test -f hello
+ then
+ do this
+ fi
+
- We prefer "test" over "[ ... ]".
- We do not write the noiseword "function" in front of shell
functions.
- - We prefer a space between the function name and the parentheses. The
- opening "{" should also be on the same line.
- E.g.: my_function () {
+ - We prefer a space between the function name and the parentheses,
+ and no space inside the parentheses. The opening "{" should also
+ be on the same line.
+
+ (incorrect)
+ my_function(){
+ ...
+
+ (correct)
+ my_function () {
+ ...
- As to use of grep, stick to a subset of BRE (namely, no \{m,n\},
[::], [==], or [..]) for portability.
of "else if" statements, it can make sense to add braces to
single line blocks.
- - We try to avoid assignments inside if().
+ - We try to avoid assignments in the condition of an "if" statement.
- Try to make your code understandable. You may put comments
in, but comments invariably tend to stale out when the code