- Case arms are indented at the same depth as case and esac lines.
+ - Redirection operators should be written with space before, but no
+ space after them. In other words, write 'echo test >"$file"'
+ instead of 'echo test> $file' or 'echo test > $file'. Note that
+ even though it is not required by POSIX to double-quote the
+ redirection target in a variable (as shown above), our code does so
+ because some versions of bash issue a warning without the quotes.
+
- 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.
+ - If you want to find out if a command is available on the user's
+ $PATH, you should use 'type <command>', instead of 'which <command>'.
+ The output of 'which' is not machine parseable and its exit code
+ is not reliable across platforms.
+
- We use POSIX compliant parameter substitutions and avoid bashisms;
namely:
- We do not use Process Substitution <(list) or >(list).
+ - Do not write control structures on a single line with semicolon.
+ "then" should be on the next line for if statements, and "do"
+ should be on the next line for "while" and "for".
+
- 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 () {
+
- As to use of grep, stick to a subset of BRE (namely, no \{m,n\},
[::], [==], nor [..]) for portability.