Two ways to handle short and long options in bash - bash

Have written two ways, trying to parse short and long options by hand. The first is complicated with the use of IFS=" =". Perhaps set -- $* is not necessary.
rando ()
{
IFSPREV="$IFS" # Save IFS (splits arguments on whitespace by default)
IFS=" =" # Split arguments on " " and "="
set -- $* # Set positional parameters to command line arguments
IFS="$IFSPREV" # Set original IFS
local iarg=0 narg="$#"
while (( narg > 0 )); do
opt="$1"
iarg=$(( iarg + 1 ))
case $opt in
("-s"|"--src"|"--source") src="$2" ; shift 2 ;;
("-d"|"--dst"|"--destin") dst="$2" ; shift 2 ;;
("--") shift 1 ; break ;;
("-"*) printf '%s\n' "Unknown option: $1" ; shift 1 ;;
(*) shift 1 ; break ;;
esac
done
}
And here is the other, but I also want to split on = for long-options.
rando ()
{
PARAMS=""
while (( "$#" )); do
case "$1" in
("-s"|"--src"|"--source")
if [ -n "$2" ] && [ ${2:0:1} != "-" ]; then
src="$2"
shift 2
else
echo "Error: Argument for $1 is missing" >&2
exit 1
fi
;;
("-d"|"--dst"|"--destin")
if [ -n "$2" ] && [ ${2:0:1} != "-" ]; then
dst="$2"
shift 2
else
echo "Error: Argument for $1 is missing" >&2
exit 1
fi
;;
-*|--*=) # unsupported flags
echo "Error: Unsupported flag $1" >&2
exit 1
;;
*) # preserve positional arguments
PARAMS="$PARAMS $1"
shift
;;
esac
done
}

Related

Parsing optional and not optional arguments

I am new with bash and after reading and trying a lot about how to parse arguments I cannot what I really want to do I want to parse optional and not optional arguments. More specifically I want to parse 3 arguments, first (a fastaq file) second (a second optional fastaq file) a third argument that will be a directory.
my_script.sh -f1 file1.fasta --f2 file2.fasta -d/home/folder1/folder2
or
my_script.sh -f1 file1.fasta -d /home/folder1/folder2
I have tried to do this in many ways but I dont know how to let the program identifies when there are two fasta files and a directory and, when there is only one fasta file and a directory.
With this arguments I want to save them in variables because they will be used later by third parties.
I have tried this:
for i in "$#"; do
case $i in
-f1=|-fasta1=)
FASTA1="${i#=}"
shift # past argument=value
;;
-d) DIRECTORY=$2
shift 2
;;
-d=|-directory=) DIRECTORY="${i#=}"
shift # past argument=value
;;
--f2=|-fasta2=) FASTA2="${i#*=}"
shift # past argument=value
;;
*)
;;
esac
done
But I just got this
scripts_my_first_NGS]$ ./run.sh -f1 fasta.fasta -d /home/folder1
FASTA1 =
DIRECTORY =
FASTA2 =
Never parse command line options on your own!
Instead either use the Bash function getopts, if you do not need GNU style long options or use use the GNU program getopt otherwise.
The following examples uses an array for FASTA. FASTA1 is ${FASTA[0]} and FASTA2 is ${FASTA[1]}. In case of getopts this makes it possible to use just one option character (-f) multiple times.
Using getopts with only one-character options:
#! /bin/bash
FASTA=()
DIRECTORY=
while getopts 'f:d:' option; do
case "$option" in
f)
FASTA+=("$OPTARG")
;;
d)
DIRECTORY="$OPTARG"
;;
*)
printf 'ERROR: Invalid argument\n' >&2
exit 1
;;
esac
done
shift $((OPTIND-1))
if [[ -z ${FASTA[0]} ]]; then
printf 'ERROR: FASTA1 missing\n' >&2
exit 1
fi
if [[ -z $DIRECTORY ]]; then
printf 'ERROR: DIRECTORY missing\n' >&2
exit 1
fi
printf 'FASTA1 = %s\n' "${FASTA[0]}"
printf 'FASTA2 = %s\n' "${FASTA[1]}"
printf 'DIRECTORY = %s\n' "$DIRECTORY"
Usage:
run -f file1.fasta -f file2.fasta -d /home/folder1/folder2
Using getopt with one-character and GNU style long options mixed:
#! /bin/bash
FASTA=()
DIRECTORY=
options=$(getopt -o d: -l f1: -l f2: -- "$#") || {
printf 'ERROR: Invalid argument\n' >&2
exit 1
}
eval set -- "$options"
while true; do
case "$1" in
--f1)
FASTA[0]="$2"
shift 2;;
--f2)
FASTA[1]="$2"
shift 2;;
-d)
DIRECTORY="$2"
shift 2;;
--)
shift
break;;
*)
break;;
esac
done
if [[ -z ${FASTA[0]} ]]; then
printf 'ERROR: FASTA1 missing\n' >&2
exit 1
fi
if [[ -z $DIRECTORY ]]; then
printf 'ERROR: DIRECTORY missing\n' >&2
exit 1
fi
printf 'FASTA1 = %s\n' "${FASTA[0]}"
printf 'FASTA2 = %s\n' "${FASTA[1]}"
printf 'DIRECTORY = %s\n' "$DIRECTORY"
Usage:
run --f1 file1.fasta --f2 file2.fasta -d /home/folder1/folder2
Basically you need to add a separate parser for versions of the options where they aren't used with the equal sign.
Also your shift commands are useless since you're processing a for loop. So convert it to to a while [[ $# -gt 0 ]]; do loop instead.
I also added a few modifications which I suggest be added.
while [[ $# -gt 0 ]]; do
case $1 in
-f1|-fasta1)
FASTA1=$2
shift
;;
-f1=*|-fasta1=*)
FASTA1=${1#*=}
;;
-d|-directory)
DIRECTORY=$2
shift
;;
-d=*|-directory=*)
DIRECTORY=${1#*=}
;;
-f2|fasta2)
FASTA2=$2
shift
;;
-f2=*|-fasta2=*)
FASTA2=${1#*=}
;;
-*)
echo "Invalid option: $1" >&2
exit 1
;;
--)
# Do FILES+=("${#:2}") maybe
break
;;
*)
# TODO
# Do FILES+=("$1") maybe
;;
esac
shift
done
The "parser" for the with-equal and non-with-equal versions of the options can also be unified by
using a helper function:
function get_opt_arg {
if [[ $1 == *=* ]]; then
__=${1#*=}
return 1
elif [[ ${2+.} ]]; then
__=$2
return 0 # Tells that shift is needed
else
echo "No argument provided to option '$1'." >&2
exit 1
fi
}
while [[ $# -gt 0 ]]; do
case $1 in
-d|-directory|-d=*|-directory=*)
get_opt_arg "$#" && shift
DIRECTORY=$__
;;
-f1|-fasta1|-f1=*|-fasta1=*)
get_opt_arg "$#" && shift
FASTA1=$__
;;
-f2|fasta2|-f2=*|-fasta2=*)
get_opt_arg "$#" && shift
FASTA2=$__
;;
-*)
echo "Invalid option: $1" >&2
exit 1
;;
--)
# Do FILES+=("${#:2}") maybe
break
;;
*)
# TODO
# Do FILES+=("$1") maybe
;;
esac
shift
done
Update
I found a complete solution to command-line parsing without relying on getopt[s] and it does it even more consistentlty: https://konsolebox.io/blog/2022/05/14/general-command-line-parsing-solution-without-using-getopt-s.html

Bash: default boolean value in getopts

I want to include a default option in my script where if the user uses this option, set the flag to true or it should be false by default. It seems that the script is not accepting false or true as boolean value. How can I make it boolean?
flag=
instructions() {
echo " -a File name" >&2
echo " -f optional boolean" flag=${flag:-false}
}
while getopts ":a:fi" option; do
case "$option" in
a ) file=$OPTARG;;
f ) flag=true;;
u )
instructions
;;
\?)
echo "Not valid -$OPTARG" >&2
instructions
;;
: ) echo "args required";;
esac
done
if [[ "$flag" != true || "$flag" != false ]]; then
echo "Not a boolean value"
fi
Check this, I made some fixes to your script (commented in the code) along with a proper formatting.
#!/bin/bash
# Set the default value of the flag variable
flag=false
instructions() {
echo "Usage: $0 [ -a FILE ] [ -f ]" >&2
echo " -a File name" >&2
echo " -f optional boolean flag=${flag:-false}" >&2
}
# If the script must be executed with options, this checks if the number of arguments
# provided to the script is greater than 0
if [ $# -eq 0 ]; then
instructions
exit 1
fi
while getopts ":a:fi" option; do
case "${option}" in
a )
file="$OPTARG"
;;
f )
flag=true
;;
i ) # "u" is not a valid option
instructions
exit 0
;;
\?)
echo "Option '-$OPTARG' is not a valid option." >&2
instructions
exit 1
;;
: )
echo "Option '-$OPTARG' needs an argument." >&2
instructions
exit 1
;;
esac
done
# Since a variable can't have 2 values assigned at the same time,
# you should use && (and) instead of || (or)
if [[ "$flag" != true ]] && [[ "$flag" != false ]]; then
echo "Not a boolean value"
fi
exit 0

Loop Script throws 0 by executing touch

I'm writing a script that makes a while loop for me, that I doesn't have to write a one line while loop again and again.
Short explanation:
The command "loop" will execute the command parameter -n times and with -p seconds pause. You can use -e to echo the command and not execute it. -v to show all parameters. Additionally its possible to use the iterator of the while loop.
Playing around with it, I've found a bug.
loop --verbose --times 5 'touch testfile$i'
#loop the touch command 5 times and generate the testfiles 0 to 4
same as:
loop -v -n 5 'touch testfile$i'
It generate "testfile0" to "testfile4" but also a file named "0"
Do somebody know why the file "0" will be generated?
And what do you think about a command like that? Would you like to use it?
Best
Steven
#!/bin/bash
# easy to use loop command
#
# Autor: Steven Wagner
# Date: 22 June 2018
# Version: 0.1
TIMES=0
FREQUENCY=0
PAUSE="0"
VERBOSE=false
ECHOONLY=false
SILENCE=false
POSITIONAL=()
while [[ $# -gt 0 ]]
do
key="$1"
case $key in
-n|--times)
temp="$2"
if [[ $temp =~ ^[[:digit:]]+$ ]];
then
TIMES=$temp
else
echo "ERROR: value is not a digit"
exit
fi
shift # past argument
shift # past value
;;
-p|--pause)
#PAUSE="$2"
temp="$2"
PAUSE=$temp
#if [[ $temp =~ ^[[:digit:]]+$ ]];
#then
# PAUSE=$temp
#else
# echo "ERROR: value is not a digit"
# exit
#fi
shift # past argument
shift # past value
;;
-v|--verbose)
VERBOSE=true
shift # past argument
;;
-e|--echo-only)
ECHOONLY=true
shift # past argument
;;
-s|--silence)
SILENCE=true
shift # past argument
;;
--*)
echo "Error \"$key\" not known"
shift #past argument
;;
-*)
i=0
while [[ $i -lt ${#key}-1 ]]
do
char=${key:$[$i+1]:1}
case $char in
v)
VERBOSE=true
;;
e)
ECHOONLY=true
;;
s)
SILENCE=true
;;
esac
(( i++ ))
done
shift # past argument
;;
*) # unknown option
POSITIONAL+=("$1") # save it in an array for later
shift # past argument
;;
esac
done
set -- "${POSITIONAL[#]}" # restore positional parameters
#Pause make sleep command
pause=""
if [ $PAUSE > 0 ]
then
pause="sleep $PAUSE"
fi
#times make while control-command
times=""
if [ $TIMES != 0 ]
then
times="[ \$i -lt \$TIMES ]"
else
times="true" #infinity loop
fi
#Echo Only
command=$#
if $ECHOONLY
then
command="echo $#"
fi
#Silence
silence=""
if $SILENCE && ! $ECHOONLY
then
silence="&>/dev/null"
fi
if $VERBOSE
then
echo "pause = $PAUSE"
if [ $TIMES != 0 ]
then
echo "times = $TIMES"
else
echo "times = infinity"
fi
if $ECHOONLY; then echo "echo only = yes"; fi
if $SILENCE; then echo "silence = yes"; fi
echo "command = '$#' $silence"
echo
fi
#start the loop
timestamp=$(date +%s%N)
eval "
i=0
while $times
do
eval '$command' $silence
$pause
(( i++ ))
done
"
if $VERBOSE
then
echo
echo "duration: $[($(date +%s%N)-$timestamp)/1000000]ms"
fi

How to bypass an optional argument for the following argument in bash?

TABLE=`echo "${1}" | tr '[:upper:]' '[:lower:]'`
if [ $1 = -d ]
then TABLE=daminundation
elif [ $1 = -b ]
then TABLE=burnscararea
elif [ $1 = -r ]
then TABLE=riverpointinundation
elif [ $1 = " " ]
then echo "User must input -d (daminundation), -b (burnscararea)
or -r (riverpointinundation)."
fi
SHAPEFILEPATH=${2}
MERGEDFILENAME=${3}
if [ -z $3 ] ;
then MERGEDFILENAME=merged.shp
else
MERGEDFILENAME=${3}
fi
COLUMNNAME=${4}
if [ -n $4 ]
then COLUMNNAME=$4
fi
$3 & $4 are optional arguments. However, if I choose not to use $3 but I want to use $4, it will read the command as $3. Confused by other methods, how should I make it so that an undesired optional command can be bypassed for the next one?
You probably want this:
#!/bin/bash
while getopts ":b :d :r" opt; do
case $opt in
b)
TABLE=burnscararea
;;
d)
TABLE=daminundation
;;
r)
TABLE=riverpointinundation
;;
\?)
echo "Invalid option: -$OPTARG" >&2
exit 1
;;
esac
done
shift $((OPTIND-1))
[ -z "$TABLE" ] && ( echo "At least one of -b/-d/-r options must be provided"; exit 1; )
[ $# -ne 3 ] && ( echo "3 params expected!"; exit 1; )
SHAPEFILEPATH="$2"
MERGEDFILENAME="$3"
COLUMNNAME="$4"
# other stuff

how to make sure that N+1 argument is present when Nth argument is equal to "--check"

I am trying to write code to check if any argument (on position N) is equal to "--check" and, if its true, require that next argument (position N+1) is present. Otherwise, exit.
How can i achieve that?
i am trying sth like this but it doesnt seem to work:
i am reiterating arguments and if "--check" is found then setting FLAG to 1 which triggers another conditional check for nextArg:
FLAG=0
for i in "$#"; do
if [ $FLAG == 1 ] ; then
nextARG="$i"
FLAG=0
fi
if [ "$i" == "--check" ] ; then
FLAG=1
fi
done
if [ ! -e $nextARG ] ; then
echo "nextARG not found"
exit 0
fi
I would go with getopts. The link shows an example how you could check for your missing parameter.
You could use a form like this. I use it as a general approach when parsing arguments. And I find it less confusing than using getopts.
while [[ $# -gt 0 ]]; do
case "$1" in
--option)
# do something
;;
--option-with-arg)
case "$2" in)
check_pattern)
# valid
my_opt_arg=$2
;;
*)
# invalid
echo "Invalid argument to $1: $2"
exit 1
;;
esac
# Or
if [[ $# -ge 2 && $2 == check_pattern ]]; then
my_opt_arg=$2
else
echo "Invalid argument to $1: $2"
exit 1
fi
shift
;;
*)
# If we don't have default argument types like files. If that is the case we could do other checks as well.
echo "Invalid argument: $1"
# Or
case $1 in
/*)
# It's a file.
FILES+=("$1")
;;
*)
# Invalid.
echo "Invalid argument: $1"
exit 1
;;
esac
esac
shift
done

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