Last modified on 13 April 2010, at 11:24

Puredyne/Coding Style

Shell ScriptingEdit

This guideline is heavily inspired from the Debian Live Coding Style.

CompatibilityEdit

  • Don't use syntax or semantics that are unique to the Bash shell. For example, the use of array constructs.
  • Only use the POSIX subset - for example, use $(foo) over `foo`.
  • You can check your scripts with 'sh -n' and 'checkbashisms'

IndentingEdit

  • Always use tabs over spaces.

WrappingEdit

  • Generally, lines are 80 chars at maximum.
  • Use the "Linux style" of line breaks:
  # Bad:
  if foo; then
      bar
  fi
 
  # Good:
  if foo
  then
      bar
  fi
  • The same holds for functions:
  #Bad:
  foo () {
      bar
  }
 
  #Good:
  foo ()
  {
      bar
  }

VariablesEdit

  • Variables are always in capital letters.
  • Use braces around variables; eg. write ${FOO} instead of $FOO.
  • Always protect variables with respect to potential whitespaces, write "${FOO}" not ${FOO}.
  • For consistency reasons, always use quotes when assigning values to variables:
  #Bad:
  FOO=bar
 
  #Good:
  FOO="bar"
  • If multiple variables are used, quote the full expression:
  #Bad:
  if [ -f "${FOO}"/foo/"${BAR}"/bar ]
  then
      foobar
  fi
 
  #Good:
  if [ -f "${FOO}/foo/${BAR}/bar" ]
  then
      foobar
  fi

MiscellaneousEdit

  • Use | as a seperator in calls to sed, e.g. sed -e 's|foo|bar|'.
  • Don't use the test command for comparisons or tests, use [ ], e.g. if [ -x /bin/foo ]; ... and not if test -x /bin/foo; ....