• sf – script framework
  • Requirements
  • Usage
    • 1. sf-variables
      • sfargs
      • sfexamples
    • 2. Include sf
    • 3. Write your script
      • Input functions
      • Output functions
      • Text formatting variables
  • Examples
    • Count
    • Add
    • Greet

sf – script framework

script framework can be used to simplify and beautify Bash scripts. It provides:

• Argument parsing
• Usage output
• Input functions
• Output functions
• Text formatting variables

All just by declaring some variables and sourcing it. Or keep your scripts self-contained and include it as an oneliner.

The usage is pretty self-explanatory once you have seen it. If you're curious and don't want to read through the documentation, head directly to the examples.

---

Here is the oneliner version of sf which was created with this tool:

  # sf -- script framework (https://github.com/Deleh/sf)
  sftrs=$'\e[0m';sftbf=$'\e[1m';sftdim=$'\e[2m';sftul=$'\e[4m';sftblk=$'\e[5m';sftinv=$'\e[7m';sfthd=$'\e[8m';sftclr=$'\e[1A\e[K';sftk=$'\e[30m';sftr=$'\e[31m';sftg=$'\e[32m';sfty=$'\e[33m';sftb=$'\e[34m';sftm=$'\e[35m';sftc=$'\e[36m';sftw=$'\e[97m';function sferr { echo "${sftbf}${sftr}ERROR${sftrs} $1";[ -z "$2" ]&&exit 1;};function sfwarn { echo "${sftbf}${sfty}WARNING${sftrs} $1";};function sfask { if [ "$2" == "" ];then read -p "$1? [${sftbf}Y${sftrs}/${sftbf}n${sftrs}] " sfin;[[ "$sfin" =~ y|Y|^$ ]]&&sfin=true||sfin=false;else read -p "$1? [${sftbf}y${sftrs}/${sftbf}N${sftrs}] " sfin;[[ "$sfin" =~ n|N|^$ ]]&&sfin=false||sfin=true;fi;};function sfget { [ "$2" != "" ]&&read -p "$1 [${sftbf}$2${sftrs}]: " sfin||read -p "$1: " sfin;[ "$sfin" == "" ]&&[ "$2" != "" ]&&sfin="$2";};function _sferr { echo "${sftbf}${sftr}SF PARSE ERROR${sftrs} $1";exit 1;};OLDIFS=$IFS;IFS=";";_sfphead="";_sfpdesc="";_sfodesc="  -h, --help;Show this help message\n";_sfexamples="";_sfpargs=();declare -A _sfflags;declare -A _sfargs;for a in "${sfargs[@]}";do _sfsubst=${a//";"};_sfcount="$(((${#a} - ${#_sfsubst})))";if [ $_sfcount -eq 1 ];then read -r -a _sfparsearr<<<"${a}";_sfpargs+=("${_sfparsearr[0]}");_sfphead="$_sfphead ${_sfparsearr[0]}";_sfpdesc="$_sfpdesc  ${_sfparsearr[0]};${_sfparsearr[1]}\n";elif [ $_sfcount -eq 2 ];then read -r -a _sfparsearr<<<"${a}";_sfflags["-${_sfparsearr[1]}"]="${_sfparsearr[0]}";_sfflags["--${_sfparsearr[0]}"]="${_sfparsearr[0]}";declare ${_sfparsearr[0]}=false;_sfodesc="$_sfodesc  -${_sfparsearr[1]}, --${_sfparsearr[0]};${_sfparsearr[2]}\n";elif [ $_sfcount -eq 4 ];then read -r -a _sfparsearr<<<"${a}";_sfargs["-${_sfparsearr[1]}"]="${_sfparsearr[0]}";_sfargs["--${_sfparsearr[0]}"]="${_sfparsearr[0]}";declare ${_sfparsearr[0]}="${_sfparsearr[3]}";_sfodesc="$_sfodesc  -${_sfparsearr[1]}, --${_sfparsearr[0]} ${_sfparsearr[2]};${_sfparsearr[4]} (default: ${_sfparsearr[3]})\n";else _sferr "Wrong argument declaration: $a";fi;done;[ "$sfparr" == true ]&&[ "${#_sfpargs[@]}" == 0 ]&&_sferr "At least one positional argument must be used with 'sfparr'";for e in "${sfexamples[@]}";do _sfsubst=${e//";"};_sfcount="$(((${#e} - ${#_sfsubst})))";if [ $_sfcount -eq 1 ];then read -r -a _sfparsearr<<<"${e}";_sfexamples="$_sfexamples  ${_sfparsearr[0]};${_sfparsearr[1]}\n";else _sferr "Wrong example declaration: $e";fi;done;IFS=$OLDIFS;function _sfusage { echo -n "Usage: $(basename $0) [OPTIONS]";echo -ne "$_sfphead";[ "$sfparr" == true ]&&echo -n " ...";echo;[ ! -z ${sfdesc+x} ]&&echo -e "\n$sfdesc";if [ "$_sfpdesc" != "" ];then echo -e "\nPOSITIONAL ARGUMENTS";echo -e "$_sfpdesc"|column -c 80 -s ";" -t -W 2;fi;if [ "$_sfodesc" != "" ];then echo -e "\nOPTIONS";echo -e "$_sfodesc"|column -c 80 -s ";" -t -W 2;fi;if [ "$_sfexamples" != "" ];then echo -e "\nEXAMPLES";echo -e "$_sfexamples"|column -c 80 -s ";" -t -W 2;fi;if [ ! -z ${sfextra+x} ];then echo -e "\n$sfextra";fi;exit 0;};for a in "$@";do [ "$a" == "-h" ]||[ "$a" == "--help" ]&&_sfusage;done;while(("$#"));do if [ ! -z ${_sfflags["$1"]} ];then declare ${_sfflags["$1"]}=true;elif [ ! -z ${_sfargs["$1"]} ];then if [ -n "$2" ]&&[ "${2:0:1}" != "-" ];then declare ${_sfargs["$1"]}="$2";shift;else sferr "Argument for '$1' missing";fi;else if [ "${1:0:1}" == "-" ];then sferr "Unsupported argument: $1";else if [ "${#_sfpargs[@]}" != 0 ];then declare ${_sfpargs[0]}="$1";[ "$sfparr" == true ]&&_sfplast="${_sfpargs[0]}"&&_sfparr=("$1");_sfpargs=("${_sfpargs[@]:1}");elif [ "$sfparr" == true ];then _sfparr+=("$1");else sferr "Too many positional arguments";fi;fi;fi;shift;done;[ "$sfparr" == true ]&&[ "${#_sfparr[@]}" -ge 1 ]&&read -r -a ${_sfplast}<<<"${_sfparr[@]}";if [ "$sfparr" != true ]&&[ ${#_sfpargs[@]} != 0 ];then for p in "${_sfpargs[@]}";do sferr "Positional argument '$p' missing" 0;done;exit 1;fi;unset a e _sfargs _sferr _sfexamples _sfflags _sfodesc _sfpargs _sfparr _sfpdesc _sfphead _sfplast _sfusage

Requirements

• At least Bash 4.x

Usage

The general usage for writing a script with sf is:

1. Declare sf-variables at the top of your script
2. Include sf
3. Write your script with already parsed arguments, input functions, output functions and text formatting variables

1. sf-variables

This is the list of variables which can be set before including sf. Everything is optional.

Name	Description	Example
sfdesc	Description of the script	sfdesc="This script does nothing."
sfargs	Array for declaration of arguments, positional arguments and flags. Look below for more information	See below
sfparr	Flag which indicates if the last declared positional argument should be treated as array	sfparr=true
sfexamples	Array for declaration of examples for the usage output. Look below for more information	See also below
sfextra	Additional usage output	sfextra="No copyright."

Examples which show the usage of all variables can be found below and in the examples directory.

sfargs

This is an array of strings. Every string defines an argument, a flag or an positional argument of the script. The type is defined by the amount of semicolons in the string.

Type	Declaration order	Example
Positional argument	<name>;<description>	sfargs+=("FILE;File to read")
Flag	<name>;<shorthand>;<description>	sfargs+=("verbose;v;Enable verbose output")
Argument	<name>;<shorthand>;<value_name>;<default_value>;<description>	sfargs+=("text;t;TEXT;done;Print TEXT when finished")

The order of declaration defines the order in the usage output.

sfexamples

This is also an array of strings. Examples are of the form <command>;<description> and can be added to sf like this:

  sfexamples+=("count 8;Count to eight")

2. Include sf

There are three methods of including sf:

1. Grab the sf file from this repo, place it next to your script and source it:

     source "$(dirname $0)/sf"

2. Copy and paste the oneliner from the top of this README

3. Source sf from the web with curl:

     source <(curl -s https://raw.githubusercontent.com/Deleh/sf/master/sf)

   Note that this adds an online dependency to your script and if sf changes, your script may break. This method should only be used for testing purposes.

3. Write your script

sf deals with missing inputs and handles the parsing of arguments. This means that after sf was included you can be sure that all variables have assigned values. Flags are either false or true, arguments have a provided value or the default value and positional arguments have a provided value.

The values are stored in variables with the name $<name>. If you declared for example a flag like this:

  sfargs+=("verbose;v;Enable verbose output")

Then the variable $verbose exists with a value of either false or true.

Input functions

User input can be requested with two functions. After calling a function, the user input is provided in the variable $sfin.

sfask	Takes a string as input and asks for yes or no. If an additional argument is provided (doesn't matter what), no will be default. $sfin is either true or false
sfget	Takes a string as input and asks for user input. If a second argument is provided, this will be the default if no user input was entered

Here is a small snippet to show the usage:

  sfget "Please enter your name" "John"
  echo "Hello $sfin"
  sfask "Do you want to proceed"
  if [ "$sfin" == true ]; then
      sfask "Are you sure" "no"
      [ "$sfin" == true ] && echo "Please continue..." || echo "Bye"
  else
      echo "Bye"
  fi

And the execution:

  Please enter your name [John]: Jane
  Hello Jane!
  Do you want to proceed? [Y/n]
  Are you sure? [y/N] y
  Please continue...

Note that the colon and question marks get added by the functions.

Output functions

Two output functions are provided which can be used to throw warnings and errors.

sfwarn	Takes a string as input and prints a warning
sferr	Takes a string as input, prints an error and exits with code 1. If an additional argument is passed (doesn't matter what), it will just throw an error and don't exit

Text formatting variables

The following text formatting variables can be used to modify the output:

sftrs	Reset formatting
sftbf	Bold
sftdim	Dim
sftul	Underline
sftblk	Blinking
sftinv	Invert foreground/background
sfthd	Hidden
sftclr	Clear the previous line
sftk	Black
sftr	Red
sftg	Green
sfty	Yellow
sftb	Blue
sftm	Magenta
sftc	Cyan
sftw	White

The variables can be used directly in echo, no -e needed. To echo the word "framework" bold and red use the variables for example like this:

  echo "${sftbf}${sftr}framework${sftrs}"

Examples

All examples can also be found in the examples directory. Play around with the sf-variables and see what happens.

Count

This example script counts from/to a number and shows the general usage of sf-variables:

  #!/usr/bin/env bash

  # ----------------------
  # sf -- script framework
  # ----------------------

  # Declare sf variables
  sfdesc="A simple counter."

  sfargs+=("N;Number to count")
  sfargs+=("reverse;r;Count reverse")
  sfargs+=("text;t;TEXT;done;Print TEXT when finished counting")

  sfexamples+=("count 8;Count to eight")
  sfexamples+=("count -r -t go 3;Count reverse from 3 and print 'go'")

  sfextra="No copyright at all."

  # Include sf, this could be replaced with a long oneliner
  source "$(dirname $0)/sf"

  # ----------------------
  # Actual script
  # ----------------------

  if [ "$N" -ge 11 ]; then                    # Use parsed positional argument
      sferr "I can only count to/from 10"     # Throw an error and exit
  fi

  counter="$N"                                # Use parsed positional argument
  echo -n "$sftbf"                            # Print everyting from here bold
  while [ "$counter" -ge 1 ]; do
      if [ "$reverse" == true ]; then         # Use parsed flag
          echo "  $counter"
      else
          echo "  $(expr $N - $counter + 1)"  # Use parsed positional argument
      fi
      counter=$(expr $counter - 1)
      sleep 1
  done
  echo -n "$sftrs"                            # Reset text formatting
  echo "$text"                                # Use parsed argument

The usage output of the counter script is:

  Usage: count [OPTIONS] N

  A simple counter.

  POSITIONAL ARGUMENTS
    N  Number to count

  OPTIONS
    -h, --help       Show this help message
    -r, --reverse    Count reverse
    -t, --text TEXT  Print TEXT when finished counting (default: done)

  EXAMPLES
    count 8           Count to eight
    count -r -t go 3  Count reverse from 3 and print 'go'

  No copyright at all.

Add

This script adds numbers and shows the usage of sfparr:

  #!/usr/bin/env bash

  # ----------------------
  # sf -- script framework
  # ----------------------

  # Declare sf variables
  sfdesc="Calculate the sum of multiple numbers."

  sfargs+=("NUMBERS;Numbers which will be added")
  sfargs+=("verbose;v;Enable verbose output")

  sfparr=true  # Treat the last declared positional argument as array

  # Include sf, this could be replaced with a long oneliner
  source "$(dirname $0)/sf"

  # ----------------------
  # Actual script
  # ----------------------

  sum=0

  for n in "${NUMBERS[@]}"; do         # Use parsed positional argument array
      if [ "$verbose" == true ]; then  # Use parsed flag
          echo -n "$sum + $n = "
      fi
      sum="$(expr $sum + $n)"
      if [ "$verbose" == true ]; then  # Use parsed flag
          echo "$sftbf$sum$sftrs"      # Use text formatting variables
      fi
  done

  echo "The sum is: $sftbf$sum$sftrs"  # Use text formatting variables

And here is the produced usage:

  Usage: add [OPTIONS] NUMBERS ...

  Calculate the sum of multiple numbers.

  POSITIONAL ARGUMENTS
    NUMBERS  Numbers which will be added

  OPTIONS
    -h, --help     Show this help message
    -v, --verbose  Enable verbose output

Greet

This example greets a user and asks for the age. It shows the usage of input functions:

  #!/usr/bin/env bash

  # ----------------------
  # sf -- script framework
  # ----------------------

  # Declare sf variables
  sfdesc="Greet a person."

  # Include sf, this could be replaced with a long oneliner
  source "$(dirname $0)/sf"

  # ----------------------
  # Actual script
  # ----------------------

  sfget "Enter your name"                    # Get input
  echo "Hello ${sfin}!"                      # Use input

  sfask "Do you want to tell me your age"    # Ask for YES/no
  if [ "$sfin" == true ]; then               # Use answer
      sfget "Enter your Age"                 # Get input
      sfask "Is $sfin really your age" "no"  # Use input and ask for yes/NO
      if [ "$sfin" == true ]; then           # Use answer
          echo "Great!"
      else
          echo "I knew it!"
      fi
  fi

The produced usage:

  Usage: greet [OPTIONS]

  Greet a person.

  OPTIONS
    -h, --help  Show this help message