Is it posseble to have a --help argument with getopts?
I'm currently using this to code the help feature:
#!/bin/bash
PROGNAME=${0##*/}
PROGVERSION=1.0
usage()
{
cat << EO
Prog description goes here.
Usage: $PROGNAME
Options:
EO
cat <<EO | column -s\& -t
-h|--help & show this output
-v|--version & show version information
EO
}
SHORTOPTS="hv"
LONGOPTS="help,version"
ARGS=$(getopt -s bash --options $SHORTOPTS \
--longoptions $LONGOPTS --name $PROGNAME -- "$#" )
eval set -- "$ARGS"
while true; do
case $1 in
-h|--help)
usage
exit 0
;;
-v|--version)
echo "$PROGVERSION"
exit 0
;;
--)
shift
break
;;
*)
shift
break
;;
esac
shift
done
The bash getopts builtin does not support long option names with the double-dash prefix. It only supports single-character options.
Related
I have a scenario where i would like to assign an option a default value but a user can decide to give it another argument:
Here is an example
check_param() {
for arg in "$#"; do
shift
case "$arg" in
"--force") set -- "$#" "-f" ;;
"--type") set -- "$#" "-t" ;;
"--help") set -- "$#" "-h" ;;
"--"*) echo "Unknown parameter: " $arg; show_help; exit 1 ;;
*) set -- "$#" "$arg"
esac
done
# Standard Variables
force=0
type="daily"
OPTIND=1
while getopts "hft:v" opt
do
case "$opt" in
"f") force=1 ;;
"t") type=${OPTARG} ;;
"h") show_help; exit 0 ;;
"?") show_help; exit 1 ;;
esac
done
shift $(expr $OPTIND - 1) # remove options from positional parameters
From the above example, i would like when the user gives the parameter -t without any argument to apply the default value which is daily , and the user can also use parameter -t with any other argument and that will be checked later in code.
The problem is now the parameter -t must be given an argument due to the colon, but i kinda need for it to do both, with or without argument.
Thanks in advance for any explanations or links to any article that can help.
So according to a suggestion i got Here is the test result
check_param() {
## Standard Variablen der Parameter
force=0
type="daily.0"
## Break down the options in command lines for easy parsing
## -l is to accept the long options too
args=$(getopt -o hft::v -l force,type::,help -- "$#")
eval set -- "$args"
## Debugging mechanism
echo ${args}
echo "Number of parameters $#"
echo "first parameter $1"
echo "Second parameter $2"
echo "third parameter $3"
while (($#)); do
case "$1" in
-f|--force) force=1; ;;
-t|--type) type="${2:-${type}}"; shift; ;;
-h|--help) show_help; exit 0; ;;
--) shift; break; ;;
*) echo "Unbekannter Parameter"; exit 1; ;;
esac
shift
done
echo ${type}
}
check_param $#
echo ${type}
The output:
sh scriptsh -t patch.0
-t '' -- 'patch.0'
Number of parameters 4
first parameter -t
Second parameter
third parameter --
daily.0
daily.0
It still didn't assign the value patch to the variable type
Is there a way in bash script to have an option to give an argument but it shouldn't a must?
Yes, there is a way.
getopts does not supports optional arguments. So... you can:
roll your own bash library for parsing arguments or
use another tool that has support for optional arguments.
A common tool is getopt that should be available on any linux.
args=$(getopt -o hft::v -l force,type::,help -- "$#")
eval set -- "$args"
while (($#)); do
case "$1" in
-f|--force) force=1; ;;
-t|--type) type="${2:-default_value}"; shift; ;;
-h|--help) echo "THis is help"; exit; ;;
--) shift; break; ;;
*) echo "Error parsgin arguments"; exit 1; ;;
esac
shift
done
getopt handles long arguments and reorders arguments, so you can ./prog file1 -t opt and ./prog -t opt file1 with same result.
I would like to build a script with getopts, that continues in the flag, when an $OPTARG isn't set.
My script looks like this:
OPTIONS=':dBhmtb:P:'
while getopts $OPTIONS OPTION
do
case "$OPTION" in
m ) echo "m"
t ) echo "t"
d ) echo "d";;
h ) echo "h";;
B ) echo "b";;
r ) echo "r";;
b ) echo "b"
P ) echo hi;;
#continue here
\? ) echo "?";;
:) echo "test -$OPTARG requieres an argument" >&2
esac
done
My aim is to continue at my comment, when there is no $OPTARG set for -P.
All I get after running ./test -P is :
test -P requieres an argument
and then it continues after the loop but I want to continue in the -P flag.
All clear?
Any Ideas?
First, fix the missing ;; in some of the case branches.
I don't think you can: you told getopts that -P requires an argument: two error cases
-P without an argument is the last option. In this case getops sees that nothing follows -P and sets the OPTION variable to :, which you handle in the case statement.
-P is followed by another option: getopts will simply take the next word, even if the next word is another option, as OPTARG.
Change the case branch to
P ) echo "P: '$OPTARG'";;
Then:
invoking the script like bash script.sh -P -m -t, the output is
P: '-m'
t
invoking the script like bash script.sh -Pmt, the output is
P: 'mt'
This is clearly difficult to work around. How do you know if the user intended the option argument to be literally "mt" and not the options -m and -t?
You might be able to work around this using getopt (see the canonical example) using an optional argument for a long option (those require an equal sign like --long=value) so it's maybe easier to check if the option argument is missing or not.
Translating getopts parsing to getopt -- it's more verbose, but you have finer-grained control
die() { echo "$*" >&2; exit 1; }
tmpArgs=$(getopt -o 'dBhmt' \
--long 'b::,P::' \
-n "$(basename "$0")" \
-- "$#"
)
(( $? == 0 )) || die 'Problem parsing options'
eval set -- "$tmpArgs"
while true; do
case "$1" in
-d) echo d; shift ;;
-B) echo B; shift ;;
-h) echo h; shift ;;
-m) echo m; shift ;;
-t) echo t; shift ;;
--P) case "$2" in
'') echo "P with no argument" ;;
*) echo "P: $2" ;;
esac
shift 2
;;
--b) case "$2" in
'') echo "b with no argument" ;;
*) echo "b: $2" ;;
esac
shift 2
;;
--) shift; break ;;
*) printf "> %q\n" "$#"
die 'getopt internal error: $*' ;;
esac
done
echo "Remaining arguments:"
for ((i=1; i<=$#; i++)); do
echo "$i: ${!i}"
done
Successfully invoking the program with --P:
$ ./myscript.sh --P -mt foo bar
P with no argument
m
t
Remaining arguments:
1: foo
2: bar
$ ./myscript.sh --P=arg -mt foo bar
P: arg
m
t
Remaining arguments:
1: foo
2: bar
This does impose higher overhead on your users, because -P (with one dash) is invalid, and the argument must be given with =
$ ./myscript.sh --P arg -mt foo bar
P with no argument
m
t
Remaining arguments:
1: arg
2: foo
3: bar
$ ./myscript.sh --Parg mt foo bar
myscript.sh: unrecognized option `--Parg'
Problem parsing options
$ ./myscript.sh -P -mt foo bar
myscript.sh: invalid option -- P
Problem parsing options
$ ./myscript.sh -P=arg -mt foo bar
myscript.sh: invalid option -- P
myscript.sh: invalid option -- =
myscript.sh: invalid option -- a
myscript.sh: invalid option -- r
myscript.sh: invalid option -- g
Problem parsing options
Do not mix logic with arguments parsing.
Prefer lower case variables.
My aim is to continue at my comment, when there is no $OPTARG set for -P
I advise not to. The less you do at one scope, the less you have to think about. Split parsing options and executing actions in separate stages. I advise to:
# set default values for options
do_something_related_to_P=false
recursive=false
tree_output=false
# parse arguments
while getopts ':dBhmtb:P:' option; do
case "$option" in
t) tree_output=true; ;;
r) recursive="$OPTARG"; ;;
P) do_something_related_to_P="$OPTARG"; ;;
\?) echo "?";;
:) echo "test -$OPTARG requieres an argument" >&2
esac
done
# application logic
if "$do_something_related_to_P"; then
do something related to P
if "$recursive"; then
do it in recursive style
fi
fi |
if "$tree_output"; then
output_as_tree
else
cat
fi
Example of "don't put programming application logic in the case branches" -- the touch command can take a -t timespec option or a -r referenceFile option but not both:
$ touch -t 202010100000 -r file1 file2
touch: cannot specify times from more than one source
Try 'touch --help' for more information.
I would implement that like (ignoring other options):
while getopts t:r: opt; do
case $opt in
t) timeSpec=$OPTARG ;;
r) refFile=$OPTARG ;;
esac
done
shift $((OPTIND-1))
if [[ -n $timeSpec && -n $refFile ]]; then
echo "touch: cannot specify times from more than one source" >&2
exit 1
fi
I would not do this:
while getopts t:r: opt; do
case $opt in
t) if [[ -n $refFile ]]; then
echo "touch: cannot specify times from more than one source" >&2
exit 1
fi
timeSpec=$OPTARG ;;
r) if [[ -n $timeSpec ]]; then
echo "touch: cannot specify times from more than one source" >&2
exit 1
fi
refFile=$OPTARG ;;
esac
done
You can see if the logic gets more complicated (as I mentioned, exactly one of -a or -b or -c), that the case statement size can easily balloon unmaintainably.
I am trying to pass some values to my bash script using named parameters similar to the following:
./script.sh --username='myusername' --password='superS3cret!' --domainou="OU=Groups with Space,OU=subou,DC=mydomain,DC=local"
I have the following code:
#!/bin/bash
while [ "$1" != "" ]; do
PARAM=`echo $1 | awk -vFPAT='([^=]*)|("[^"]+")' -vOFS="=" '{print $1}'`
VALUE=`echo $1 | awk -vFPAT='([^=]*)|("[^"]+")' -vOFS="=" '{print $2}'`
case $PARAM in
-u | --username)
username=$VALUE
;;
-p | --password)
password=$VALUE
;;
-ou | --domainou)
domainou=$VALUE
;;
*)
echo "ERROR: unknown parameter \"$PARAM\""
exit 1
;;
esac
shift
done
echo $username
echo "$password"
echo "$domainou"
What I get when I run my script is:
myusername
superS3cret!
OU
Now the first two lines are correct but obviously I don't want OU...
I want:
OU=Groups with Space,OU=subou,DC=mydomain,DC=local
Awk seems to be matching the = inside the quote. As best as I can tell the way to solve that is using
-vFPAT='([^=]*)|("[^"]+")' -vOFS="="
But clearly that's not working so I am just wondering if any awk gurus can help me understand what's wrong with my awk statement.
Thanks
Brad
You can do it like this:
#!/bin/bash
while [ $# -gt 0 ]; do
case "$1" in
-u=* | --username=*)
username="${1#*=}"
;;
-p=* | --password=*)
password="${1#*=}"
;;
-ou=* | --domainou=*)
domainou="${1#*=}"
;;
*)
printf "Error: unknown option: $1\n"
exit 1
esac
shift
done
printf "username: $username\n"
printf "password: $password\n"
printf "domainou: $domainou\n"
For parsing command line options that include both long and short optoins, consider using GNU getopt, which has support for long options. While it is possible to build-your-own parser replacement, using the getopt provides for more robust parsing:
Abbreviation of options (e.g., accepting --user for --username).
Checking for required/optional values
Error handling
See also: Using getopts to process long and short command line options
set $(getopt --long 'username:,password:,ou:,domain:' -o 'u:p:' -- "$0" "$#")
while [ "$#" -gt 0 ] ; do
OP=$1
shift
case "$OP" in
--) PROG=$1 ; shift ; break ;;
-u | --username) username=$1 ; shift ;;
-p | --password) password=$1 ; shift ;;
--ou | --domain) domainou=$1 ; shift ;;
esac
done
# Positional arguments are set ...
Below is what ultimately worked best for me.
#dash-o definitely got me pointed in the right direction but the script you provided was printing out extraneous info:
set: usage: set [-abefhkmnptuvxBCHP] [-o option-name] [--] [arg ...]
I believe the offending line was this:
set --long 'username:,password:,ou:,domain:' -o 'u:p:' -- "$0" "$#"
Here's the code that accomplished what I needed. I can't take credit for this. I stole it from here Using getopts to process long and short command line options but I never would have found that if not for dash-o so a big thank you!
#!/bin/bash
die() { echo "$*" >&2; exit 2; } # complain to STDERR and exit with error
needs_arg() { if [ -z "$OPTARG" ]; then die "No arg for --$OPT option"; fi; }
while getopts ab:c:-: OPT; do
# support long options: https://stackoverflow.com/a/28466267/519360
if [ "$OPT" = "-" ]; then # long option: reformulate OPT and OPTARG
OPT="${OPTARG%%=*}" # extract long option name
OPTARG="${OPTARG#$OPT}" # extract long option argument (may be empty)
OPTARG="${OPTARG#=}" # if long option argument, remove assigning `=`
fi
case "$OPT" in
u | username ) needs_arg; username="$OPTARG" ;;
p | password ) needs_arg; password="$OPTARG" ;;
o | domainou ) needs_arg; domainou="$OPTARG" ;;
??* ) die "Illegal option --$OPT" ;; # bad long option
\? ) exit 2 ;; # bad short option (error reported via getopts)
esac
done
shift $((OPTIND-1)) # remove parsed options and args from $# list
echo "$username"
echo "$password"
echo "$domainou"
I just wrote a script in bash, which work expect for multi long option:
#!/bin/bash
OPTS=`getopt -q -o fdhl: -l free,df,help,log: -- "$*"`
#Check if error with getopt
if [ $? != 0 ]
then
echo -e "error: parameter could not be found\n\nUsage:\n supervision [options]\n\n Try 'supervision --help'\n or 'supervision -h'\n for additional help text." ;
exit 1
fi
eval set -- "$OPTS"
while true ; do
case "$1" in
-f|--free)
free -h ;
shift;;
-d|--df)
df -h ; #Run df system command
shift;;
-l|--log)
case "$2" in
"") echo "miss file" ;
shift 2;; #No file passed as parameter
*)
df -h >> "$2" ;
shift 2;;
esac ;;
-h|--help) #Display help
shift;;
--) #End of parsed parameters list
shift ; break ;;
*)
break ;;
esac
done
I don't get why i'm supposed to, when I use more than 1 long option, for example:
sh myscript --free --df
And when I use --log:
sh myscript --log logfile
Both case exit on the if [ $? != 0 ], seems like the element which follow the 1st long option doesn't get parsed.
Ok, I figured out and it's all due to the using of "$*" instead of "$#" in the getopt call. I don't exactly why, i guessed both do the same thing, but it turns out to be the one which causes the problem.
Here's a snippet that I use to parse options in Bash:
#!/bin/bash
PROGNAME=${0##*/}
PROGVERSION=0.1
wW='-4.5.5-double'
reName=
usage()
{
cat << EO
Script purpose goes here.
EO
cat <<EO | column -s\& -t
-h, --help & show this output
-r, --rename & renames confout to Your gro
-v, --version & show version information
-w, --workWith & gromax exec suffix
EO
}
SHORTOPTS="hvw:r"
LONGOPTS="help,version,workWith:rename"
ARGS=$(getopt -s bash --options $SHORTOPTS --longoptions $LONGOPTS --name $PROGNAME -- "$#")
eval set -- "$ARGS"
while true; do
case $1 in
-h|--help)
usage; exit 0;;
-v|--version)
echo "$PROGVERSION"; exit 0;;
-w|--workWith)
wW=$2; shift;;
-r|--rename)
reName="true"; shift;;
--)
shift; break;;
*)
shift; break;;
esac
shift
done
# ====================
## finally the script:
echo "rename:" $reName
echo ' wW:' $wW
This snippet parses option (-w) only if it is before the trigger (-r):
~/wrk/mlDn/vas/res/bbst: test.bash -w 'dfdff' -r
rename: true
wW: dfdff
~/wrk/mlDn/vas/res/bbst: test.bash -r -w 'dfdff'
rename: true
wW: -4.5.5-double
How can this be fixed? What is wrong with my snippet?
Remove the call to shift from the -r processing. It's removing the -w from ARGS.
The problem is that you are shifting twice: once when you see the -r option and then again when you exit the case statement. This causes you to jump over the -w option. Therefore, you should only shift once. Remove the shift from outside the case statement and do all the shifting inside it.
Change your code to:
while true; do
case $1 in
-h|--help)
usage; exit 0;;
-v|--version)
echo "$PROGVERSION"; exit 0;;
-w|--workWith)
wW=$2; shift 2;; # shift twice here
-r|--rename)
reName="true"; shift;;
--)
shift; break;;
*)
shift; break;;
esac
#shift # this shift is not required
done
echo "rename:" $reName
echo ' wW:' $wW