How to handle more than 10 parameters in shell

Question

I am using bash shell on linux and want to use more than 10 parameters in shell script

Note that having 10 parameters will make it quite confusing. Perhaps it would be better to use options (e.g. -a 1 or --foo=bar) instead. See man getopt, man getopts, and man bash for some options for doing that. — Mikel, Commented Feb 6, 2011 at 10:34
See also: Why do bash command line arguments after 9 require curly brackets? — John Kugelman, Commented Apr 3, 2020 at 16:37

Dennis Williamson · Accepted Answer · 2022-06-26 15:55:43Z

240

Use curly braces to set them off:

echo "${10}"

Any positional parameter can be saved in a variable to document its use and make later statements more readable:

city_name=${10}

If fewer parameters are passed then the value at the later positions will be unset.

You can also iterate over the positional parameters like this:

for arg

or

for arg in "$@"

or

while (( $# > 0 ))    # or [ $# -gt 0 ]
do
    echo "$1"
    shift
done

answered Feb 6, 2011 at 10:27

Dennis Williamson

356k93 gold badges379 silver badges442 bronze badges

5

Note that ${10} will work in bash, but will limit your portability since many implementations of sh only allow single digit specifications.
– William Pursell
Commented Feb 6, 2011 at 14:11
2

@William: There are some shells that won't accept it, such as the original legacy Bourne shell, but in addition to the shells I listed in another comment (Bash, dash, ksh and zsh), it also works in csh, tcsh and Busybox ash.
– Dennis Williamson
Commented Feb 6, 2011 at 15:34
3

@WilliamPursell ${10} is defined by POSIX
– Zombo
Commented Dec 9, 2016 at 19:15
4

Worrying about ${10} working is only necessary when using very old implementations which are not standard compliant. Probably only of historical interest...and yet I have yet to ever use it! I suppose because best practice dictates that 10 arguments is way too many unless they are repeated, in which case you'll iterate over them with "$@" rather than enumerating them.
– William Pursell
Commented Dec 10, 2016 at 16:54

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szafran · Accepted Answer · 2020-03-29 05:05:58Z

39

You can have up to 256 parameters from 0 to 255 with:

${255}

szafran

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answered Feb 6, 2011 at 10:29

lukuluku

4,3843 gold badges31 silver badges35 bronze badges

8

I think that limit is dependent on the shell. Bash, dash, ksh and zsh don't seem to have it. sh -c 'echo ${333}' /usr/bin/*
– Dennis Williamson
Commented Feb 6, 2011 at 10:33
6

My shell comfortably goes up to 2 million set $(seq 2097152); echo ${2097152}
– Zombo
Commented Dec 9, 2016 at 19:32
3

You can run getconf ARG_MAX to find out the max number of parameters your system can handle.
– Lorand
Commented Jan 17, 2023 at 2:45

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2 Answers 2