How to include custom command options in a bash script with $1 and $2?

bash shell-script command-line scripting arguments

6,103

Solution 1

Since you are listing bash as the shell used, type:

$ help getopts

Which will print something like:

getopts: getopts optstring name [arg]
Parse option arguments.

Getopts is used by shell procedures to parse positional parameters as options.

OPTSTRING contains the option letters to be recognized; if a letter is followed by a colon, the option is expected to have an argument, which should be separated from it by white space.

Each time it is invoked, getopts will place the next option in the shell variable $name, initializing name if it does not exist, and the index of the next argument to be processed into the shell variable OPTIND. OPTIND is initialized to 1 each time the shell or a shell script is invoked. When an option requires an argument, getopts places that argument into the shell variable OPTARG.

Getopts normally parses the positional parameters ($0 - $9), but if more arguments are given, they are parsed instead.

Solution 2

You should to use man 1 bash:

Small example:

#!/bin/bash

while getopts "a:b:" opt      # get options for -a and -b ( ':' - option has an argument )
do
    case $opt in
        a) echo "Option a: $opt, argument: $OPTARG";;
        b) echo "Option b: $opt, argument: $OPTARG";;
    esac
done

6,103

Anonymous

Updated on September 18, 2022

Comments

Anonymous over 1 year
I have a script myscript.sh
```
#!/bin/sh

echo $1 $2
```
which is used something like ...
```
./myscript.sh foo bar
```
which gives me an output of ...
```
foo bar
```
but how can i make this script include custom command options? for example ...
```
./myscript.sh -a foo and corespond to $1
```
and
```
./myscript.sh -b bar and corespond to $2
```
FreeSoftwareServers almost 5 years

A small example is like a picture, worth a thousand words!
FreeSoftwareServers almost 5 years

Assuming you can read code and it's got comments lol
Yurij Goncharuk almost 5 years

@roaima I've add man page about getopt (I hurried with answer) but example was about getopts. I omitted : also. That`s why I've been downvoted. I think so. Maybe the problem in something else.
Anonymous almost 5 years

@YurijGoncharuk maybe because man 1 bash is not man 1 getopts ? That being said, I upvoted you! I also appreciated the man 1 bash link as it would do me very well to read it. So thanks my man! :)