Created
February 22, 2012 15:48
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rc-file reading in a shell script
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| #!/usr/bin/env zsh | |
| # An example script that reads a colon separated rc file, given on argv | |
| # Line format expected: | |
| # option: value | |
| # Mind the colon and space separating option name from the value. | |
| # Adjust the parameter expansion as needed if you change the line format. | |
| # - read <var> will read a line at a time. | |
| # - Piping the file name into the while block reads the file into the read call. | |
| # - typeset -A <var> explicitly marks a hash for ZSH. | |
| # declare -A <var> is the same for bash. | |
| # - Fancypants parameter expansion gives us opts[option]=value. | |
| # - Quoting the value allows is to be any valid string, which generally means | |
| # that the value will be anything between the colon and the next newline character. | |
| if [[ -f $1 ]]; then | |
| typeset -A opts | |
| while read l; do | |
| opts[${l%%:*}]="${l##*: }" | |
| done < $1 | |
| fi | |
| echo "Number of found options: ${#opts[*]}" | |
| for k in ${(k)opts}; do | |
| echo "$k => ${opts[$k]}" | |
| done |
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Of course, there are other ways to read options from a file. For one, you could simply have it be a regular shell script defining variables, and source it. On the upside, anything valid in a shell script can go there, so you can work some magic on your configuration. On the downside, your config file is a shell script which will be executed upon sourcing, which is good and bad, depending on how prone you are to accidentally writing things like
rm -rf ~in your files.Certain applications may require sectioned config files, like the traditional ini-file syntax, where sections are separated with
[Header]lines. This kind of configuration will require some sed/awk magic, and storing the options will also become a lot more complicated, since shells only support one-dimension arrays. At the very least, you'll be dealing with a section list in one array, and one array per section to store it's options.