# general

1. Try to make code readable. This is the most important rule.
Turn your eyes away from code and look on it again.
If you cannot quickly understand the code, reformat to make it better.

2. Avoid semicolons, just because they make code harder to read (see rule 1).

# variables

## defining
```bash
typeset var          # avoid local - it breaks code in some rare cases
typeset -a arr
arr=()               # define and reset array. required for arr+=( ... )
typeset -x important # the same export, just for consistency
```

Variables defined in one local in function are available in all other functions called by it.

## numeric variables comparison
```bash
: variable:${variable:=0} # Ensures it is set and simplifies debugging
(( variable ))      # when not zero
(( variable == 0 )) # when zero
: $(( variable++ )) # increase
```

## string variables comparison
```bash
[[ -n "${var:-}" ]]       # var is set
[[ "${var:-}" == "bla" ]] # var equals bla
[[ -n "${var1:-}" &&      # multi line check, first check has to be after [[ - for Zsh
  -n "${var2:-}" &&
  -n "${var3:-}"
]]
```

## multiple values check
```
case "$action" in
  (show)
    cat $1
    ;;
  (edit)
    ${EDITOR:-vim} $1
    ;;
  (help)
    echo "Usage this [show|edit]"
    ;;
esac
```

## dynamic invocation
```bash
_show(){ cat $1 || return $?; }
_edit(){ ${EDITOR:-vim} $1 || return $?; }
action=_$1
shift
${action} "$@" ||
case $? in
  (127) echo "Unknown action '$action'." ;;
  (*)   echo "Error '$?' occurred."      ;;
esac
```

# if's

## dens form for short statements / commands
```bash
if [[ -n "${bla:-}" ]]
then x=bla
else x=
fi
```

## sparse form for long statements / more commands
```bash
if
  [[ -n "${bla_asd_sf_affdfs_dsf_sdf_sdf:-}" ]] ||
  [[ -n "${bar_Dfs_dsg_FG_fd_fd_df_dfgdf:-}" ]]
then
  some more commands
  and even more
else
  or other commands
fi
```

## mixed for large else
```bash
if [[ -n "${bla:-}" ]]
then x=bla
else
  x=...
  some more commands
  and even more
fi
```

## just else
```bash
[[ -n "${bla:-}" ]] ||
{
  x=...
  some more commands
  and even more
}
```

# loops

## params parsing
```bash
while
  (( $# ))
do
  case "$1" in
    (-s|--silent)
      silent_flag=1
      ;;
    (-n|--name)
      (( $# > 1 )) ||
      {
        printf "ERROR: name required"
        exit 1
      }
      bla_name_flag="$2"
      shift
      ;;
    (*)
      bla_extra_flags+=( "$1" )
      ;;
  esac
  shift
done
```

## params iterate
```bash
# the - in "$@" - is default
for __param
do echo "$__param"
done
```