I am trying to extend the getopts from the sourced script as below.
if an option other than a,b,c,d is passed in, it needs to print "invalid option" and exit.
script_a.sh:
#!/bin/bash
script_a_getopts() {
while getopts 'a:b:' OPT; do
case "$OPT" in
a)
a=$OPTARG
;;
b)
b=$OPTARG
;;
*)
echo "invalid option"
exit 1
;;
esac
done
}
script_b.sh
#!/bin/bash
source script_a.sh
while getopts ':c:d:' OPT; do
case "$OPT" in
c)
c=$OPTARG
;;
d)
d=$OPTARG
;;
[?])
script_a_getopts $#
esac
done
echo "a=$a"
echo "b=$b"
echo "c=$c"
echo "d=$d"
When I run the script, it don't work as expected, obviously I am making a mistake.
$ ./script_b.sh -c cat -d dog -a apple -b boy
a=
b=
c=cat
d=dog
Didn't throw error when -x is passed.
$ ./script_b.sh -x
a=
b=
c=
d=
Short Answer: You have to rollback the OPTIND before calling script_a_getopts.
case "$OPT" in
c)
c=$OPTARG
;;
...
[?])
let OPTIND--
script_a_getopts $#
esac
done
Long Answer:
The getopts track which arguments have been processed using the OPTIND variable. When the top getopts recognized unknown item, it has already 'consumed' it by moving OPTIND to the next argument. To get script_a_getopts to process that argument, the OPTIND need to be rolled back to point to the unprocessed argument.
The let OPTIND-- will allow the unrecognized argument to be re-processed.
Side note, if you want to allow options to be placed in arbitrary order (-c cat -a apple -d dog -b boy) you will have to repeat the same in the script_a_getopts. This will require improved error processing in script_a_getopts function.
Related
Background
In bash I have a working getopts interface as depicted below:
while getopts "a:b:c:d:" OPTION ; do
case "$OPTION" in
a) JET="$OPTARG" ;;
b) FUEL="$OPTARG" ;;
c) CAN="$OPTARG" ;;
d) MELT="$OPTARG" ;;
*) echo "Usage $0 -a A -b B -c C -d D"; exit 1 ;;
esac
done
shift $((OPTIND-1))
#Check out input parameters
for PARAM in JET FUEL CAN MELT; do
echo "$PARAM in [${!PARAM}]"
done
Question
What is the cshell translation for this? I cannot find a clear example of getopts (with an s) in cshell, yet there is an easily findable one for bash. This is distinct from attempting to use getopt, since getopts is an entirely different function from getopt.
I want to do two things in this script:
1) pass a file name to the script
2) pass options to the script
example 1:
$./test_script.sh file_name_to_be_read
pass only file names to script
example 2:
$./test_script.sh -a -b file_name_to_be_read
pass file name and options to script
I am able to get example 1 to work using the following codes:
while read -r line ; do
echo $line
done
In example 2, I want to add additional flags like these:
while getopts "abc opt; do
case "$opt" in
a) a=1
echo "a is enabled"
;;
b) b=1
echo "b is enabled"
;;
esac
done
but how do I make it so that the file_name to be mandatory and be used with or without options?
getopts only parses options (arguments starting with -); the other arguments are left alone. The parameter OPTIND tells you the index of the first argument not yet looked at; typically you discard the options before this.
while getopts "ab" opt; do
case "$opt" in
a) a=1
echo "a is enabled"
;;
b) b=1
echo "b is enabled"
;;
esac
done
shift $((OPTIND - 1))
echo "$# arguments remaining"
for arg in "$#"; do
echo "$arg"
done
The preceding, if called as bash tmp.bash -a -b c d e, produces
$ bash tmp.bash -a -b c d e
a is enabled
b is enabled
3 arguments remaining:
c
d
e
This is my entire script in its simplest form.
#!/bin/bash
src=""
targ=${PWD}
while getopts "s:t:" opt; do
case $opt in
s)
src=$OPTARG
;;
t)
targ=$OPTARG
;;
esac
shift $((OPTIND-1))
done
echo "Source: $src"
echo "Target: $targ"
I run this script as getopts_test -s a -t b
However, it always prints the pwd in front of the Target: and never b
What am I missing here?
The reason for why b is never printed is that the shift within the loop moves the processed options away after the first iteration, i.e. after a has been printed. Use of shift $((OPTIND-1)) is intended to access the possible given variadic parameters. Naturally, once you remove shift, targ gets reassigned to b, and ${PWD} is no longer included in it since you don't have concatenation of the strings (targ and the option of -t) anywhere.
An alternative to what #glenn-jackman suggested in his comment
would be this :
#!/bin/bash
src=""
targ=${PWD}
while getopts "s:t:" opt; do
case $opt in
s)
src=$OPTARG
echo "Source: $src"
;;
t)
targ=$OPTARG
echo "Target: $targ"
;;
esac
done
shift $((OPTIND-1)) # Turning to non-option arguments say a file name and so on.
Here you go with the natural flow of arguments without shifting.
I'd like to pass options as a parameter. E.g.:
mycommand -a 1 -t '-q -w 111'
The script cannot recognize a string in quotes. I.e it gets only part of the string.
getopts works the same - it see only -q.
For custom getopts I use similar script (example):
while :
do
case $1 in
-h | --help | -\?)
# Show some help
;;
-p | --project)
PROJECT="$2"
shift 2
;;
-*)
printf >&2 'WARN: Unknown option (ignored): %s\n' "$1"
shift
;;
*) # no more options. Stop while loop
break
;;
--) # End of all options
echo "End of all options"
shift
break
;;
esac
done
Maybe I misunderstand the question, but getopts seems to work for me:
while getopts a:t: arg
do
case $arg in
a) echo "option a, argument <$OPTARG>"
;;
t) echo "option t, argument <$OPTARG>"
;;
esac
done
Run:
bash gash.sh -a 1 -t '-q -w 111'
option a, argument <1>
option t, argument <-q -w 111>
Isn't that what you want? Maybe you missed the : after the options with arguments?
I am trying to parse two options which both need an argument.
#!/bin/bash
while getopts "a:b:" opt; do
case $opt in
a)
echo "a has the argument $OPTARG."
shift
;;
b)
echo "b has the argument $OPTARG."
shift
;;
esac
done
What I expect is that this script prints out the arguments of a and b. But the output is only:
$ sh ./cmd_parse_test.sh -a foo -b bar
a has the argument foo.
What am I doing wrong?
You don't have to shift to get the next argument. Simply dump whatever you want, and continue for the next iteration, as in:
#!/bin/bash
while getopts "a:b:" opt; do
case $opt in
a)
echo "a has the argument $OPTARG."
;;
b)
echo "b has the argument $OPTARG."
;;
esac
done
Which outputs:
$ ./cmd_parse_test.sh -a foo -b bar
a has the argument foo.
b has the argument bar.
Notice also that you don't have to run the script with sh, since you've already set the shbang to use bash.