#!/usr/bin/env bash

# @(#) s2       Demonstrate shellcheck.

# Utility functions: print-as-echo, print-line-with-visual-space, debug.
# export PATH="/usr/local/bin:/usr/bin:/bin"
LC_ALL=C ; LANG=C ; export LC_ALL LANG
pe() { for _i;do printf "%s" "$_i";done; printf "\n"; }
pl() { pe;pe "-----" ;pe "$*"; }
em() { pe "$*" >&2 ; }
db() { ( printf " db, ";for _i;do printf "%s" "$_i";done;printf "\n" ) >&2 ; }
db() { : ; }
C=$HOME/bin/context && [ -f $C ] && $C shellcheck

FILE=${1-s1}

pl " Input data file $FILE:"
cat $FILE

pl " Results:"
shellcheck $FILE

exit 0

$ ./s2

Environment: LC_ALL = C, LANG = C
(Versions displayed with local utility "version")
OS, ker|rel, machine: Linux, 3.16.0-4-amd64, x86_64
Distribution        : Debian 8.6 (jessie) 
bash GNU bash 4.3.30
ShellCheck - shell script analysis tool

-----
 Input data file s1:
#!/usr/bin/env ksh

# @(#) s1       Demonstrate forms for function definition.

# Utility functions: print-as-echo, print-line-with-visual-space, debug.
# export PATH="/usr/local/bin:/usr/bin:/bin"
LC_ALL=C ; LANG=C ; export LC_ALL LANG
pe() { for _i;do printf "%s" "$_i";done; printf "\n"; }
pl() { pe;pe "-----" ;pe "$*"; }
em() { pe "$*" >&2 ; }
db() { ( printf " db, ";for _i;do printf "%s" "$_i";done;printf "\n" ) >&2 ; }
db() { : ; }
C=$HOME/bin/context && [ -f "$C" ] && . "$C"
pe

function a {
  echo " From a"
  return
}

b() {
  echo " From b"
  return
}

function c() {
  echo " From c"
  return
}

a
b
c

exit 0

-----
 Results:

In s1 line 26:
function c() {
^-- SC2111: ksh does not allow 'function' keyword and '()' at the same time.

shellcheck      analyse shell scripts (man)
Path    : /usr/bin/shellcheck
Version : ShellCheck - shell script analysis tool
Type    : ELF 64-bit LSB executable, x86-64, version 1 (SYSV ...)
Help    : probably available with -h
Repo    : Debian 8.6 (jessie) 
Home    : http://hackage.haskell.org/package/ShellCheck