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';sfthdn=$'\e[8m';sftclr=$'\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 -e "${sftbf}${sftr}ERROR${sftrs} $1";[ -z "$2" ]&&exit 1;};function sfwarn { echo -e "${sftbf}${sfty}WARNING${sftrs} $1";};function sfask { if [ -n "$2" ];then echo -ne "$1? [${sftbf}y${sftrs}/${sftbf}N${sftrs}] ";read -r sfin;[[ "$sfin" =~ n|N|^$ ]]&&sfin=false||sfin=true;else echo -ne "$1? [${sftbf}Y${sftrs}/${sftbf}n${sftrs}] ";read -r sfin;[[ "$sfin" =~ y|Y|^$ ]]&&sfin=true||sfin=false;fi;};function sfget { if [ -n "$2" ];then read -r -p "$1 [${sftbf}$2${sftrs}]: " sfin;else read -r -p "$1: " sfin;fi;[ "$sfin" == "" ]&&[ "$2" != "" ]&&sfin="$2";};function _sferr { echo "${sftbf}${sftr}SF PARSE ERROR${sftrs} $1";exit 1;};OLDIFS=$IFS;IFS=";";_sfpargs=();_sfpheads=();_sfpoffset=0;_sfptails=();_sfpusage="";_sfoheads=();_sfooffset=0;_sfotails=();declare -A _sfflags;declare -A _sfargs;sfargs=("${sfargs[@]}" "help;h;Show this help message and exit");for a in "${sfargs[@]}";do _sfsubst=${a//";"};_sfcount="$((${#a} - ${#_sfsubst}))";if [ "$_sfcount" -eq 1 ];then read -r -a _sfparsearr<<<"${a}";[[ " ${_sfpargs[*]} " =~ " ${_sfparsearr[0]} " ]]&&_sferr "${sftbf}${_sfparsearr[0]}${sftrs} is already set: ${sftbf}${a}${sftrs}";_sfpargs+=("${_sfparsearr[0]}");_sfpusage="$_sfpusage ${_sfparsearr[0]}";_sfphead="${_sfparsearr[0]}";[ "${#_sfphead}" -gt "${_sfpoffset}" ]&&_sfpoffset="${#_sfphead}";_sfpheads+=("$_sfphead");_sfptails+=("${_sfparsearr[1]}");elif [ "$_sfcount" -eq 2 ];then read -r -a _sfparsearr<<<"${a}";[ -n "${_sfflags["--${_sfparsearr[0]}"]}" ]&&_sferr "${sftbf}${_sfparsearr[0]}${sftrs} is already set: ${sftbf}${a}${sftrs}";_sfflags["--${_sfparsearr[0]}"]="${_sfparsearr[0]}";[ -n "${_sfflags["-${_sfparsearr[1]}"]}" ]&&_sferr "${sftbf}${_sfparsearr[1]}${sftrs} is already set: ${sftbf}${a}${sftrs}";_sfflags["-${_sfparsearr[1]}"]="${_sfparsearr[0]}";declare "${_sfparsearr[0]//-/_}"=false;_sfohead="-${_sfparsearr[1]}, --${_sfparsearr[0]}";[ "${#_sfohead}" -gt "${_sfooffset}" ]&&_sfooffset="${#_sfohead}";_sfoheads+=("$_sfohead");_sfotails+=("${_sfparsearr[2]}");elif [ "$_sfcount" -eq 4 ];then read -r -a _sfparsearr<<<"${a}";[ -n "${_sfargs["--${_sfparsearr[0]}"]}" ]&&_sferr "${sftbf}${_sfparsearr[0]}${sftrs} is already set: ${sftbf}${a}${sftrs}";_sfargs["--${_sfparsearr[0]}"]="${_sfparsearr[0]}";[ -n "${_sfargs["-${_sfparsearr[1]}"]}" ]&&_sferr "${sftbf}${_sfparsearr[1]}${sftrs} is already set: ${sftbf}${a}${sftrs}";_sfargs["-${_sfparsearr[1]}"]="${_sfparsearr[0]}";declare "${_sfparsearr[0]//-/_}"="${_sfparsearr[3]}";_sfohead="-${_sfparsearr[1]}, --${_sfparsearr[0]} ${_sfparsearr[2]}";[ "${#_sfohead}" -gt "${_sfooffset}" ]&&_sfooffset="${#_sfohead}";_sfoheads+=("$_sfohead");[ "${_sfparsearr[3]}" != "" ]&&_sfotails+=("${_sfparsearr[4]} (default: ${_sfparsearr[3]})")||_sfotails+=("${_sfparsearr[4]}");else _sferr "Wrong argument declaration: ${sftbf}${a}${sftrs}";fi;done;_sfeheads=();_sfetails=();_sfeoffset=0;for e in "${sfexamples[@]}";do _sfsubst=${e//";"};_sfcount="$((${#e} - ${#_sfsubst}))";if [ "$_sfcount" -eq 1 ];then read -r -a _sfparsearr<<<"${e}";_sfehead="${_sfparsearr[0]}";[ "${#_sfehead}" -gt "${_sfeoffset}" ]&&_sfeoffset="${#_sfehead}";_sfeheads+=("$_sfehead");_sfetails+=("${_sfparsearr[1]}");else _sferr "Wrong example declaration: ${sftbf}${e}${sftrs}";fi;done;IFS=$OLDIFS;[ "$sfparr" == true ]&&[ "${#_sfpargs[@]}" == 0 ]&&_sferr "At least one positional argument must be used with ${sftbf}sfparr${sftrs}";[ "$sfparr" == true ]&&_sfpusage="${_sfpusage% *} [${_sfpusage##* } ...]";_sfpoffset=$(("_sfpoffset" + 3));_sfooffset=$(("_sfooffset" + 3));_sfeoffset=$(("_sfeoffset" + 3));_sfwidth=$(stty size|cut -d ' ' -f 2);_sfpdesc="";for i in "${!_sfptails[@]}";do _sfptail="${_sfptails[$i]}";if [ "$((${#_sfptail} + _sfpoffset))" -gt "$_sfwidth" ];then _sftmpwidth="$((_sfwidth - _sfpoffset))";_sftmpwidth=$(echo -e "${_sftmpwidth}\n1"|sort -nr|head -n 1);_sfptail=$(echo "$_sfptail"|fold -s -w "$_sftmpwidth");_sfptail="${_sfptail//$' \n'/$'\n;'}";fi;_sfpdesc="${_sfpdesc} ${_sfpheads[$i]};${_sfptail}\n";done;_sfodesc="";for i in "${!_sfotails[@]}";do _sfotail="${_sfotails[$i]}";if [ "$((${#_sfotail} + _sfooffset))" -gt "$_sfwidth" ];then _sftmpwidth="$((_sfwidth - _sfooffset))";_sftmpwidth=$(echo -e "${_sftmpwidth}\n1"|sort -nr|head -n 1);_sfotail=$(echo "$_sfotail"|fold -s -w "$_sftmpwidth");_sfotail="${_sfotail//$' \n'/$'\n;'}";fi;_sfodesc="${_sfodesc} ${_sfoheads[$i]};${_sfotail}\n";done;_sfexamples="";for i in "${!_sfetails[@]}";do _sfetail="${_sfetails[$i]}";if [ "$((${#_sfetail} + _sfeoffset))" -gt "$_sfwidth" ];then _sftmpwidth="$((_sfwidth - _sfeoffset))";_sftmpwidth=$(echo -e "${_sftmpwidth}\n1"|sort -nr|head -n 1);_sfetail=$(echo "$_sfetail"|fold -s -w "$_sftmpwidth");_sfetail="${_sfetail//$' \n'/$'\n;'}";fi;_sfexamples="${_sfexamples} ${_sfeheads[$i]};${_sfetail}\n";done;function _sfusage { echo -n "Usage: $(basename "$0") [OPTIONS]";echo -ne "$_sfpusage";echo;[ -n "${sfdesc}" ]&&echo -e "\n$sfdesc"|fold -s -w "$_sfwidth";if [ "$_sfpdesc" != "" ];then echo -e "\nPOSITIONAL ARGUMENTS";echo -e "$_sfpdesc"|column -s ";" -t;fi;if [ "$_sfodesc" != "" ];then echo -e "\nOPTIONS";echo -e "$_sfodesc"|column -s ";" -t;fi;if [ "$_sfexamples" != "" ];then echo -e "\nEXAMPLES";echo -e "$_sfexamples"|column -s ";" -t;fi;[ -n "${sfextra}" ]&&echo -e "\n$sfextra"|fold -s -w "$_sfwidth";exit 0;};for a in "$@";do [ "$a" == "-h" ]||[ "$a" == "--help" ]&&_sfusage;done;for d in "${sfdeps[@]}";do if ! command -v "$d"&>/dev/null;then sferr "Command ${sftbf}${d}${sftrs} not found" 0;_sfdeperr=true;fi;done;[ "$_sfdeperr" == true ]&&exit 1;while(("$#"));do if [ -n "${_sfflags["$1"]}" ];then declare "${_sfflags["$1"]//-/_}"=true;elif [ -n "${_sfargs["$1"]}" ];then if [ -n "$2" ]&&[ "${2:0:1}" != "-" ];then declare "${_sfargs["$1"]//-/_}"="$2";shift;else sferr "Argument for ${sftbf}${1}${sftrs} missing";fi;else if [ "${1:0:1}" == "-" ];then sferr "Unsupported argument/flag ${sftbf}${1}${sftrs}";else if [ "${#_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 ]&&[ "${#_sfparr[@]}" -gt 0 ]&&read -r -a "${_sfplast?}"<<<"${_sfparr[@]}";[ "$sfparr" == true ]&&[ "${#_sfpargs[@]}" -gt 0 ]&&unset '_sfpargs[${#_sfpargs[@]}-1]';if [ "${#_sfpargs[@]}" -gt 0 ];then for p in "${_sfpargs[@]}";do sferr "Positional argument ${sftbf}${p}${sftrs} missing" 0;done;exit 1;fi;unset a d e i OLDIFS _sfargs _sfehead _sfeheads _sfeoffset _sferr _sfetails _sfexamples _sfflags _sfodesc _sfohead _sfoheads _sfooffset _sfotails _sfpargs _sfparr _sfpdesc _sfphead _sfpheads _sfplast _sfpoffset _sfptails _sfpusage _sftmpwidth _sfusage _sfwidth- At least Bash 4.x
The general usage for writing a script with sf is:
- Declare sf-variables at the top of your script
- Include sf
- Write your script with already parsed arguments, input functions, output functions and text formatting 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" |
sfdeps | Array for declaration of script dependencies. An error is thrown if one ore more of the set command are not available | sfdeps=("ffmpeg" "opusinfo") |
Examples which show the usage of all variables can be found below and in the examples directory.
This is an array of strings. Every string defines an argument, a flag or a 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.
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")There are three methods of including sf:
- Grab the sf file from this repo, place it next to your script and source it:
source "$(dirname $0)/sf"
- Copy and paste the oneliner from the top of this README
- Source sf from the web for example with
curl:source <(curl -s https://raw.githubusercontent.com/Deleh/sf/main/sf)
Note that this adds an online dependency to your script AND that sourcing from a web resource might be a potential security issue. The main branch should only be used for testing purposes in this method. Replace
mainin the URL with a commit hash to prevent future changes in sf breaking 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.
Note that dashes in declared sfargs variable names get replaced with underscores.
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. $sfin is either true or false |
sfget | Takes a string as input and asks for user input. If a second argument is provided, this will be the default if no user input was entered |
Note that the functions append a colon/question mark to the given string.
Look at the greet example to see the functions in action.
Two output functions are provided which can be used to throw warnings and errors.
sfwarn | Takes a string as input and prints a warning |
sferr | Takes a string as input, prints an error and exits with code 1. If an additional argument is passed (doesn’t matter what), it will just throw an error and don’t exit |
The following text formatting variables can be used to modify the output:
sftrs | Reset formatting |
sftbf | Bold |
sftdim | Dim |
sftul | Underlined |
sftblk | Blinking |
sftinv | Invert foreground/background |
sfthdn | Hidden |
sftclr | Clear the previous line |
sftk | Black |
sftr | Red |
sftg | Green |
sfty | Yellow |
sftb | Blue |
sftm | Magenta |
sftc | Cyan |
sftw | White |
The variables can be used directly in echo, no -e needed.
To echo the word “framework” bold and red use the variables for example like this:
echo "${sftbf}${sftr}framework${sftrs}"Look at the clear example to see some of them in action.
All examples can also be found in the examples directory.
Play around with the sf-variables and see what happens.
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" -gt 10 ]; 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 [ "$counter" -gt 0 ]; do
if [ "$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 argumentThe usage output of the script is:
Usage: count [OPTIONS] N A simple counter. POSITIONAL ARGUMENTS N Number to count OPTIONS -r, --reverse Count reverse -t, --text TEXT Print TEXT when finished counting (default: done) -h, --help Show this help message and exit EXAMPLES count 8 Count to eight count -r -t go 3 Count reverse from 3 and print 'go' No copyright at all.
An example call looks like this:
$ ./count -r -t go 3 3 2 1 go
This script shows the usage of color formatting variables and $sftclr:
#!/usr/bin/env bash
# ----------------------
# sf -- script framework
# ----------------------
# Declare sf variables
sfdesc="Show the usage of color variables and \$sftclr."
# Include sf, this could be replaced with a long oneliner
source "$(dirname $0)/sf"
# ----------------------
# Actual script
# ----------------------
echo -n "${sftbf}" # Output everything from here bold
echo "${sftr}These" # Red
sleep 0.5
echo "${sftm}lines" # Magenta
sleep 0.5
echo "${sftb}will" # Blue
sleep 0.5
echo "${sftc}delete" # Cyan
sleep 0.5
echo "${sftg}themselves" # Green
sleep 1
echo "${sfty}now!" # Yellow
sleep 0.5
echo -n "${sftclr}${sftclr}${sftclr}${sftclr}${sftclr}${sftclr}" # Clear six lines
echo "${sftblk}${sftr}T${sftm}a${sftb}d${sftc}a${sftg}a${sfty}!" # Blinking colorful
echo -n "${sftrs}" # Reset text formattingThe produced usage is:
Usage: clear [OPTIONS] Show the usage of color variables and $sftclr. OPTIONS -h, --help Show this help message and exit
The execution results in this:
$ ./clear Tadaa!
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 variablesAnd here is the produced usage:
Usage: add [OPTIONS] [NUMBERS ...] Calculate the sum of multiple numbers. POSITIONAL ARGUMENTS NUMBERS Numbers which will be added OPTIONS -v, --verbose Enable verbose output -h, --help Show this help message and exit
An example call looks like this:
$ ./add -v 1 2 3 4 5 0 + 1 = 1 1 + 2 = 3 3 + 3 = 6 6 + 4 = 10 10 + 5 = 15 The sum is: 15
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."
sfargs+=("pretty-useless-flag;p;This is a pretty useless flag which is only used to show correct linebreaks of the usage. Change your terminal size and let this print again to see how the output adapts to your window")
sfargs+=("ask-for-lastname;l;Ask for lastname")
# Include sf, this could be replaced with a long oneliner
source "$(dirname $0)/sf"
# ----------------------
# Actual script
# ----------------------
sfget "Enter your name" # Get input
echo "Hello ${sfin}!" # Use input
if [ "$ask_for_lastname" == true ]; then # Use variable with underscores instead of dashes
sfget "Enter your lastname" # Get input
echo "Ah I see, your lastname is ${sfin}" # Use input
fi
sfask "Do you want to tell me your age" # Ask for YES/no
if [ "$sfin" == true ]; then # Use answer
sfget "Enter your Age" "80" # Get input with default value
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
fiThe produced usage:
Usage: greet [OPTIONS]
Greet a person.
OPTIONS
-p, --pretty-useless-flag This is a pretty useless flag which is only used to
show correct linebreaks of the usage. Change your
terminal size and let this print again to see how
the output adapts to your window
-l, --ask-for-lastname Ask for lastname
-h, --help Show this help message and exit
An example call looks like this:
$ ./greet Enter your name: Jane Hello Jane! Do you want to tell me your age? [Y/n] Enter your Age [80]: 75 Is 75 really your age? [y/N] y Great!
This example shows the usage of sfdeps:
#!/usr/bin/env bash
# ----------------------
# sf -- script framework
# ----------------------
# Declare sf variables
sfdesc="A script that shows the usage of 'sfdeps'. It should always throw an error."
sfdeps=("source" "nonexistent" "alsononexistent" "echo")
# Include sf, this could be replaced with a long oneliner
source "$(dirname $0)/sf"
# ----------------------
# Actual script
# ----------------------
echo "If you see this, the commands 'source', 'nonexistent', 'alsononexistent' and 'echo' are available."The usage output:
Usage: throw [OPTIONS] A script that shows the usage of 'sfdeps'. It should always throw an error. OPTIONS -h, --help Show this help message and exit
And the execution:
$ ./throw ERROR Command nonexistent not found ERROR Command alsononexistent not found