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Output of “sed –help” on a terminal<\/p><\/div>\r\n
A good script would handle the arguments & options provided to it in an efficient way and outputs clear help\/usage information. \u00a0One of the commands which the unix shells support is “GetOpt” which’s a in-built command, which can be used to parse arguments & options provided to it. \u00a0However, it’s not as user-friendly and feature rich as GetOpts function supported by programming languages like Perl, which can not only parse the options & arguments but also can store the values of some of those options in variables with intuitive names. \u00a0<\/p>\r\n
As an example, let’s say you are developing a bash shell-script ‘sample.sh’<\/strong><\/em> which you want it to support 3 options:<\/p>\r\n Ever wondered, how easy it would be, if I can get a template which can:<\/p>\r\n It would make the life of scripting so easy and take away the burden of handling all of these so that you can stay focussed on programming the main task. \u00a0This is what I have tried to accomplish in the template file below. \u00a0The ‘main’\u00a0<\/strong><\/em>function is the one you would use to code the main tasks while the other functions implement what I talked above. \u00a0You might want to modify the ‘Help’\u00a0<\/em><\/strong>function to output the appropriate usage information. \u00a0You might also want to edit the ‘GetOpts’<\/strong><\/em>\u00a0call on line #191 below to include additional options in the format ‘f|file:\\’\u00a0<\/strong><\/em>at line #194 and so on. \u00a0The colon ‘:’ after the name of the long option tells the ‘GetOpts’ <\/strong><\/em>function that this particular option needs an argument.<\/p>\r\n On Linux OS, the template should work as is without any issues. \u00a0As the GNU command line toolset which ships with the Linux is one of the best with lots of features.<\/p>\r\n On Mac, you need to get the following installed before you could run this template<\/p>\r\n I have named this template as sample.sh to run it on the shell.<\/p>\r\n Output with “–help” or “-h” options<\/p><\/div>\r\n Output with “–version” or “-v” option<\/p><\/div>\r\n <\/p>\r\n Output when a wrong option (say ‘-a’) is given<\/p><\/div>\r\n Please feel free to reach out with any questions or comment. You can use the Contact Us <\/a>to write to us.<\/p>\r\n\r\n
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Linux:<\/h3>\r\n
Mac OS:<\/h3>\r\n
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Outputs:<\/h3>\r\n
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sample.sh<\/h3>\r\n\r\n\r\n
\r\n#!\/bin\/bash\r\n\r\n#************************************************************#\r\n## \t\t\t\t\t$_PGR.sh \t\t\t\t \t #\r\n## \t\t\t\twritten by Amjad khan\t\t\t #\r\n##\t\t\tEmail: khan.amjadull@gmail.com\t\t #\r\n##\t\t\tPhone: +91-9900497591\t\t\t\t \t #\r\n##\t\t\t \t \t #\r\n## #\r\n## #\r\n#************************************************************#\r\n\r\n##************ Define some functions ******##\r\n\r\n##----------------- Version? --------------##\r\n## Give the version information and exit ##\r\n## Command line options -v or --version\t ##\r\n## Exit status is 0\t\t\t\t\t\t ##\r\n##-----------------------------------------##\r\nfunction version()\r\n{\r\n\tVER=$(echo '$Revision$' | sed -e 's\/.*: \/\/; s\/ .*\/\/; s\/\\$Revision\\$\/0.0\/')\r\n\tYEAR=$(date +%Y)\r\n\t\r\n\tcat <<- ___VERSION_INFO___\r\n\t$MY_PRG ###utility### $VER\r\n\tWritten by Amjad khan\r\n\r\n\tCopyright (C) $YEAR - GRAPES PVT LTD\r\n\tAll rights reserved.\r\n\t___VERSION_INFO___\r\n\r\n\texit 0\r\n}\r\n\r\n\r\n##----------------- Help ----------------##\r\n## Give the help information and exit\t ##\r\n## Command line options -h or --help\t ##\r\n## Exit status is 0\t\t\t\t\t\t ##\r\n##---------------------------------------##\r\nfunction Help()\r\n {\r\n\tcat <<- ___HELP_MESSAGE___\r\n\tUsage: $MY_PRG [OPTION]... [FILE]...\r\n\r\n\r\n\tExamples: \r\n\t $MY_PRG\t\t\t# Comments\r\n\r\n\t## ---<description>---\r\n\r\n\tMandatory arguments to long options are mandatory for short options too.\r\n\r\n\t## ---<explanation for args>---\r\n \r\n \r\n\t -h, --help\tdisplay this help and exit\r\n\t -v, --version\toutput version information and exit\r\n\r\n\t## ---<extra info>---\r\n\r\n\tReport bugs to <khan.amjadull@gmail.com>.\r\n\t___HELP_MESSAGE___\r\n\r\n\texit 0\r\n}\r\n\r\n\r\n##----------------- Cleanup ----------------##\r\n## Clean up temporary files\t\t\t\t\t##\r\n## Exit status is 0\t\t\t\t\t\t\t##\r\n##------------------------------------------##\r\nfunction cleanup_tmpfiles {\r\n\trm -rf $_TMP\r\n}\r\n\r\n\r\n\r\n##--------- Syntax error :( ---------##\r\n## Help to try Help\t\t\t\t\t ##\r\n##-----------------------------------##\r\nfunction try_help {\t\t# Direct the user to get some help\t\t\r\n\techo "Try \\`$MY_PRG --help' for more information" && exit 1\t\t\r\n}\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\r\n\r\n\r\n##---------------- Getopts ------------------##\r\n## Utility very similar to perl getopts ##\r\n## Can handle long options and set variables ##\r\n##-------------------------------------------##\r\nfunction Getopts(){\r\n\r\n\tdeclare shorts\r\n\tdeclare longs\r\n\tdeclare same\r\n\tdeclare -a args\r\n\tlocal index\r\n\r\n\tuntil [ "$1" = "--" ] ; do\r\n\r\n\t\tif echo $1 |grep -q -P '^\\S\\|\\S+:$'; then\r\n\t\t\tshorts=(${shorts[@]} ${1%|*}:)\r\n\t\t\tlongs=(${longs[@]} ${1#*|})\r\n\t\t\tsame=(${same[@]} $1);\r\n\t\r\n\t\telif echo $1 |grep -q -P '^\\S\\|\\S+$'; then\r\n\t\t\tshorts=(${shorts[@]} ${1%|*})\r\n\t\t\tlongs=(${longs[@]} ${1#*|})\r\n\t\t\tsame=(${same[@]} $1);\r\n\t\r\n\t\telif echo $1 |grep -q -P '^\\S+\\|\\S:$'; then\r\n\t\t\tlongs=(${longs[@]} ${1%|*}:)\r\n\t\t\tshorts=(${shorts[@]} ${1#*|})\r\n\t\t\tsame=(${same[@]} $1);\r\n\t\r\n\t\telif echo $1 |grep -q -P '^\\S+\\|\\S$'; then\r\n\t\t\tlongs=(${longs[@]} ${1%|*})\r\n\t\t\tshortss=(${shorts[@]} ${1#*|})\r\n\t\t\tsame=(${same[@]} $1);\r\n\r\n\t\telif echo $1 |grep -q -P '^\\S:?$';then\r\n\t\t\tshorts=(${shorts[@]} $1);\r\n\t\r\n\t\telif echo $1 |grep -q -P '^\\S\\S+:?$'; then\r\n\t\t\tlongs=(${longs[@]} $1);\r\n\t\r\n\t\tfi\r\n\t\tshift;\r\n\tdone\r\n\r\n\tshift;\r\n\r\n\tshorts=${shorts[@]}\t\t\t\r\n\r\n\tlongs=${longs[@]}\r\n\r\n\tregex=${longs\/\/ \/\\|}\r\n\tregex=${regex\/\/:\/\\\\S*}\r\n\r\n\tsame=${same[@]\/\/:\/}\r\n\r\n\tfor option in "$@";do\r\n\t\tif echo $option|grep -q -P '^--';then\r\n\r\n\t\t\techo $option|grep -q -P "^--($regex)\\b"\r\n\r\n\t\t\t[ "$?" = "1" ] && echo "$MY_PRG: unrecognized option '$option'" && return 1;\r\n\t\tfi\t\r\n\tdone;\r\n\r\n\tregex=$(echo ${same}|sed -e 's: :\/;s\/\\\\<:g;s:|:\\\\>\/:g;s:^:\\\\<:')\r\n\t\r\n\targs=($(getopt -l ${longs\/\/ \/,} -o ${shorts\/\/ \/,} -n $MY_PRG -s bash -- $@))\r\n\t\r\n\t[ "$?" = 1 ] && return 1;\r\n\r\n\tlet index=0;\r\n\r\n\twhile [ "${args[$index]}" != "--" ];do\r\n\r\n\t\tif [ ! -z "${args[$index]%%\\'*}" ];then\r\n\r\n\t \toption=$(echo opt${args[$index]}|sed -e "s\/$regex\/;s\/-\\+\/_\/g")\r\n\t \teval $option=1;\r\n\t\telse\r\n\t\t\teval $option=${args[$index]\/\/\\'\/}\r\n\t fi\r\n\r\n\t\tlet index+=1\r\n\tdone\t \r\n}\r\n\r\n\r\n##---------------- main --------------------##\r\n\r\n##-------------------------------------------##\r\nfunction main(){\r\ntrue;\r\n}\r\n#*********************************************#\r\n\r\n## Some script wide variables\r\nMY_PRG=`basename $0`\r\n_DATE=`date +%y%m%d%H%M`\r\n\r\n## Some global variables\r\ndeclare _TMP;\t## Holds temporary files for cleanup\r\n\r\n## Valid command line options\r\nGetopts \\\r\n\t'h|help'\\\r\n\t'v|version'\\\r\n\t-- $@\r\n\r\n[ "$?" = "1" ] && try_help;\r\n\r\n[ ! -z $opt_help ] && Help;\r\n\r\n[ ! -z $opt_version ] && version;\r\n\r\ntime main;\r\nexit;\r\n###################################################\r\n## $Log$\r\n###################################################\r\n\r\n\r\n<\/pre><\/div>\r\n\r\n\r\n