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Line 12: | Line 12: | ||
<pre> | <pre> | ||
arg="a b c" | arg="a b c" | ||
set ${arg} | set - ${arg} | ||
</pre> | </pre> | ||
assigns "a", "b", "c" to [[Bash_Environment_Variables#Positional_Parameters_.241.2C_.242.2C_...|positional parameters]] $1, $2 and $3. | assigns "a", "b", "c" to [[Bash_Environment_Variables#Positional_Parameters_.241.2C_.242.2C_...|positional parameters]] $1, $2 and $3. '-' on the set command line prevents arguments that start with "--..." to interfere with [[bash set#Overview|set]] function. If "-" is not specified, and the first of the space-separated arguments contains '--', set will try to interpret that sequence of characters and will produce: | ||
set: --: invalid option | |||
set: --: invalid option | |||
==List Separator== | ==List Separator== |
Revision as of 01:11, 24 September 2017
External
- set man page http://linuxcommand.org/lc3_man_pages/seth.html
- https://www.gnu.org/software/bash/manual/html_node/The-Set-Builtin.html
Internal
set and Positional Parameters
arg="a b c" set - ${arg}
assigns "a", "b", "c" to positional parameters $1, $2 and $3. '-' on the set command line prevents arguments that start with "--..." to interfere with set function. If "-" is not specified, and the first of the space-separated arguments contains '--', set will try to interpret that sequence of characters and will produce:
set: --: invalid option
List Separator
The default list separator is space. That can be changed by setting the value of the IFS variable before executing set.
Example:
arg="a,b,c" IFS="," set ${arg}
will identically assign "a", "b", "c" to positional parameters $1, $2 and $3.
- Note you must set IFS back to whitespace after setting it to something else, so the basic shell function work as expected. This is done as shown here: restoring the default IFS value.
For more details about IFS see: