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Size: 8858
Comment: If the parenthesis are there, only the first argument of the option is stored in OPTARG (thought it does not matter in this example).
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Size: 9331
Comment: Revert the last change. Add an option that takes two arguments. Improve usage and put it in a function. Add general syntax error checking.
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| Deletions are marked like this. | Additions are marked like this. |
| Line 8: | Line 8: |
| optspec=":h-:" while getopts "$optspec" optchar do case "${optchar}" in -) case "${OPTARG}" in loglevel) eval val="\${$OPTIND}"; OPTIND=$(( OPTIND + 1 )) echo "Parsing option: '--${OPTARG}', value: '${val}'" >&2 ;; loglevel=*) val=${OPTARG#*=} opt=${OPTARG%=$val} echo "Parsing option: '--${opt}', value: '${val}'" >&2 ;; esac ;; h) echo "usage: $0 [--loglevel[=]<value>]" >&2 exit 2 ;; esac done # End of file }}} In practice, this example is so obfuscated that it may be preferable to add concatenated option support (like `-vf filename`) to a manual parsing loop instead, if that was the only reason for using `getopts`. Here's an improved and more generalized version of above attempt to add support for long options when using `getopts`: {{{#!highlight bash #!/bin/bash # Uses bash extensions. Not portable as written. |
usage() { echo "Usage:" echo " $0 [ --loglevel=<value> | --loglevel <value> | -l <value> ] [ --range <beginning> <end> ] [--] [non-option-argument]..." echo " $0 [ --help | -h ]" echo echo "Default loglevel is 0. Default range is 0 to 0" } # set defaults loglevel=0 r1=0 # beginning of range r2=0 # end of range i=$(($# + 1)) # index of the first non-existing argument |
| Line 44: | Line 23: |
| longoptspec=( [loglevel]=1 ) #use associative array to declare how many arguments a long option expects, in this case we declare that loglevel expects/has one argument, long options that aren't listed in this way will have zero arguments by default optspec=":h-:" |
# Use associative array to declare how many arguments a long option # expects. In this case we declare that loglevel expects/has one # argument and range has two. Long options that aren't listed in this # way will have zero arguments by default. longoptspec=( [loglevel]=1 [range]=2 ) optspec=":l:h-:" |
| Line 50: | Line 33: |
| if [[ "${OPTARG}" =~ .*=.* ]] #with this --key=value format only one argument is possible | if [[ ${OPTARG} =~ .*=.* ]] # with this --key=value format only one argument is possible |
| Line 52: | Line 35: |
| Line 53: | Line 37: |
| ((${#opt} <= 1)) && { echo "Syntax error: Invalid long option '$opt'" >&2 exit 2 } if (($((longoptspec[$opt])) != 1)) then echo "Syntax error: Option '$opt' does not support this syntax." >&2 exit 2 fi |
|
| Line 54: | Line 47: |
| ((OPTIND--)) | |
| Line 57: | Line 49: |
| OPTARG=${@:OPTIND:$((longoptspec[$opt]))} | ((${#opt} <= 1)) && { echo "Syntax error: Invalid long option '$opt'" >&2 exit 2 } OPTARG=(${@:OPTIND:$((longoptspec[$opt]))}) ((OPTIND+=longoptspec[$opt])) echo $OPTIND ((OPTIND > i)) && { echo "Syntax error: Not all required arguments for option '$opt' are given." >&2 exit 3 } |
| Line 59: | Line 61: |
| ((OPTIND+=longoptspec[$opt])) continue #now that opt/OPTARG are set we can process them as if getopts would've given us long options ;; loglevel) loglevel=$OPTARG |
continue #now that opt/OPTARG are set we can process them as # if getopts would've given us long options ;; l|loglevel) loglevel=$OPTARG ;; range) r1=${OPTARG[0]} r2=${OPTARG[1]} |
| Line 66: | Line 73: |
| echo "usage: $0 [--loglevel[=]<value>]" >&2 | usage exit 0 ;; ?) echo "Syntax error: Unknown short option '$OPTARG'" >&2 exit 2 ;; *) echo "Syntax error: Unknown long option '$opt'" >&2 |
| Line 73: | Line 88: |
| echo "Loglevel: $loglevel" echo "Range: $r1 to $r2" echo "First non-option-argument (if exists): ${!OPTIND-}" |
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| Line 75: | Line 94: |
| With this version you can have long and short options side by side and you shouldn't need to modify the code from line 10 to 22. This solution can also handle multiple arguments for long options, just use ${OPTARG} or ${OPTARG[0]} for the first argument, ${OPTARG[1]} for the second argument, ${OPTARG[2]} for the third argument and so on. It has the same disadvantage of its predecessor in not being portable and specific to bash. Additionally, it breaks arguments with whitespace (line 18) for long options, when given using the syntax that does not include equal sign (=). | With this version you can have long and short options side by side and you shouldn't need to modify the code from line 26 to 60. This solution can also handle multiple arguments for long options, just use ${OPTARG} or ${OPTARG[0]} for the first argument, ${OPTARG[1]} for the second argument, ${OPTARG[2]} for the third argument and so on. It has the same disadvantage of its predecessor in not being portable and specific to bash. Additionally, it breaks arguments with whitespace (line 49) for long options, when given using the syntax that does not include equal sign (=). |
getopts long option trickery
Here is an example which claims to parse long options with getopts. The basic idea is quite simple: just put "-:" into the optstring. This trick requires a shell which permits the option-argument (i.e. the filename in "-f filename") to be concatenated to the option (as in "-ffilename") as POSIX requires. The POSIX standard says you should pass arguments to options as separate options (to avoid problems with empty arguments) but requires getopts to handle the case where the argument is stuck to the option in the same argument. However, POSIX leaves the behaviour unspecified when an option is not alpha-numerical, so POSIX does not guarantee this to work. However, it should work in all of bash, dash, yash, zsh and all implementations of ksh, the only exception reported so far being posh.
1 #!/bin/bash
2 # Uses bash extensions. Not portable as written.
3
4 usage() {
5 echo "Usage:"
6 echo " $0 [ --loglevel=<value> | --loglevel <value> | -l <value> ] [ --range <beginning> <end> ] [--] [non-option-argument]..."
7 echo " $0 [ --help | -h ]"
8 echo
9 echo "Default loglevel is 0. Default range is 0 to 0"
10 }
11
12 # set defaults
13 loglevel=0
14 r1=0 # beginning of range
15 r2=0 # end of range
16
17 i=$(($# + 1)) # index of the first non-existing argument
18 declare -A longoptspec
19 # Use associative array to declare how many arguments a long option
20 # expects. In this case we declare that loglevel expects/has one
21 # argument and range has two. Long options that aren't listed in this
22 # way will have zero arguments by default.
23 longoptspec=( [loglevel]=1 [range]=2 )
24 optspec=":l:h-:"
25 while getopts "$optspec" opt; do
26 while true; do
27 case "${opt}" in
28 -) #OPTARG is name-of-long-option or name-of-long-option=value
29 if [[ ${OPTARG} =~ .*=.* ]] # with this --key=value format only one argument is possible
30 then
31
32 opt=${OPTARG/=*/}
33 ((${#opt} <= 1)) && {
34 echo "Syntax error: Invalid long option '$opt'" >&2
35 exit 2
36 }
37 if (($((longoptspec[$opt])) != 1))
38 then
39 echo "Syntax error: Option '$opt' does not support this syntax." >&2
40 exit 2
41 fi
42 OPTARG=${OPTARG#*=}
43 else #with this --key value1 value2 format multiple arguments are possible
44 opt="$OPTARG"
45 ((${#opt} <= 1)) && {
46 echo "Syntax error: Invalid long option '$opt'" >&2
47 exit 2
48 }
49 OPTARG=(${@:OPTIND:$((longoptspec[$opt]))})
50 ((OPTIND+=longoptspec[$opt]))
51 echo $OPTIND
52 ((OPTIND > i)) && {
53 echo "Syntax error: Not all required arguments for option '$opt' are given." >&2
54 exit 3
55 }
56 fi
57
58 continue #now that opt/OPTARG are set we can process them as
59 # if getopts would've given us long options
60 ;;
61 l|loglevel)
62 loglevel=$OPTARG
63 ;;
64 range)
65 r1=${OPTARG[0]}
66 r2=${OPTARG[1]}
67 ;;
68 h|help)
69 usage
70 exit 0
71 ;;
72 ?)
73 echo "Syntax error: Unknown short option '$OPTARG'" >&2
74 exit 2
75 ;;
76 *)
77 echo "Syntax error: Unknown long option '$opt'" >&2
78 exit 2
79 ;;
80 esac
81 break; done
82 done
83
84 echo "Loglevel: $loglevel"
85 echo "Range: $r1 to $r2"
86 echo "First non-option-argument (if exists): ${!OPTIND-}"
87
88 # End of file
With this version you can have long and short options side by side and you shouldn't need to modify the code from line 26 to 60. This solution can also handle multiple arguments for long options, just use ${OPTARG} or ${OPTARG[0]} for the first argument, ${OPTARG[1]} for the second argument, ${OPTARG[2]} for the third argument and so on. It has the same disadvantage of its predecessor in not being portable and specific to bash. Additionally, it breaks arguments with whitespace (line 49) for long options, when given using the syntax that does not include equal sign (=).
Silly repeated brute-force scanning
Another approach is to check options with if statements "on demand". A function like this one may be useful:
1 #!/bin/bash
2
3 HaveOpt ()
4 {
5 local needle=$1
6 shift
7
8 while [[ $1 == -* ]]
9 do
10 # By convention, "--" means end of options.
11 case "$1" in
12 --) return 1 ;;
13 $needle) return 0 ;;
14 esac
15
16 shift
17 done
18
19 return 1
20 }
21
22 HaveOpt --quick "$@" && echo "Option quick is set"
23
24 # End of file
and it will work if script is run as:
- YES: ./script --quick
- YES: ./script -other --quick
but will stop on first argument with no "-" in front (or on --):
- NO: ./script -bar foo --quick
- NO: ./script -bar -- --quick
Of course, this approach (iterating over the argument list every time you want to check for one) is far less efficient than just iterating once and setting flag variables.
It also spreads the options throughout the program. The literal option --quick may appear a hundred lines down inside the main body of the program, nowhere near any other option name. This is a nightmare for maintenance.
Complex nonstandard add-on utilities
bhepple suggests the use of process-getopt (GPL licensed) and offers this example code:
PROG=$(basename $0)
VERSION='1.2'
USAGE="A tiny example using process-getopt(1)"
# call process-getopt functions to define some options:
source process-getopt
SLOT=""
SLOT_func() { [ "${1:-""}" ] && SLOT="yes"; } # callback for SLOT option
add_opt SLOT "boolean option" s "" slot
TOKEN=""
TOKEN_func() { [ "${1:-""}" ] && TOKEN="$2"; } # callback for TOKEN option
add_opt TOKEN "this option takes a value" t n token number
add_std_opts # define the standard options --help etc:
TEMP=$(call_getopt "$@") || exit 1
eval set -- "$TEMP" # just as with getopt(1)
# remove the options from the command line
process_opts "$@" || shift "$?"
echo "SLOT=$SLOT"
echo "TOKEN=$TOKEN"
echo "args=$@"Here, all information about each option is defined in one place making for much easier authoring and maintenance. A lot of the dirty work is handled automatically and standards are obeyed as in getopt(1) - because it calls getopt for you.
Actually, what the author forgot to say was that it's actually using getopts semantics, rather than getopt. I ran this test:
~/process-getopt-1.6$ set -- one 'rm -rf /' 'foo;bar' "'" ~/process-getopt-1.6$ call_getopt "$@" -- 'rm -rf /' 'foo;bar' ''\'''
It appears to be intelligent enough to handle null options, whitespace-containing options, and single-quote-containing options in a manner that makes the eval not blow up in your face. But this is not an endorsement of the process-getopt software overall; I don't know it well enough. -GreyCat
It's written and tested on Linux where getopt(1) supports long options. For portability, it tests the local getopt(1) at runtime and if it finds an non-GNU one (ie one that does not return 4 for getopt --test) it only processes short options. It does not use the bash builtin getopts(1) command. -bhepple
Rearranging arguments
If you want to mix flags and arguments here's a function to rearrange all options to place flags first. Use before doing your normal getopts parsing.
1 arrange_opts() {
2 local flags args optstr=$1
3 shift
4
5 while (($#)); do
6 case $1 in
7 --) args+=("$@")
8 break;
9 ;;
10 -*) flags+=("$1")
11 if [[ $optstr == *"${1: -1}:"* ]]; then
12 flags+=("$2")
13 shift
14 fi
15 ;;
16 * ) args+=("$1")
17 ;;
18 esac
19 shift
20 done
21 OPTARR=("${flags[@]}" "${args[@]}")
22 }
23
24 example() {
25 local OPTIND OPTARR optstring=ab:cd
26
27 printf 'before arrange:'
28 printf '<%s>' "$@"
29 echo
30
31 arrange_opts "$optstring" "$@"
32 set -- "${OPTARR[@]}"
33
34 printf 'after arrange:'
35 printf '<%s>' "$@"
36 printf \\n\\n
37
38 printf flag:arg\\n
39
40 OPTIND=1
41 while getopts "$optstring" opt; do
42 case $opt in
43 a|c|d) printf %s\\n "$opt" ;;
44 b ) printf b:%s\\n "$OPTARG" ;;
45 \? ) printf badopt:%s\\n "$OPTARG" ;;
46 : ) printf noarg:%s\\n "$OPTARG" ;;
47 * ) printf wtf:%s\\n "$opt" ;;
48 esac
49 done
50 shift $((OPTIND-1))
51
52 printf \\nargs:
53 printf '<%s>' "$@"
54 echo
55 }
56
57 example -ad foo -b bar baz