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scripting-team: add some more details to parameter_expansion.html

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git-svn-id: svn+ssh://atelier.inf.usi.ch/home/bevilj/group-1@168 a672b425-5310-4d7a-af5c-997e18724b81
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terehm 2018-11-14 06:22:53 +00:00
parent 8b65602402
commit c0be1e502f
1 changed files with 6 additions and 0 deletions

6
site/pages/scripts/parameter_expansion.html
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@ -60,6 +60,8 @@ Example: <code>lastname=${fullname:$firstnamelength};</code><br>
This is equal to the substring of the value of VARIABLE, starting at the character with (0-based) index FROM with length LENGTH<br>
If FROM is negative, the substring starts FROM characters before the end of the string.<br>
Example: <code>lastname=${middlename:$firstnamelength:$middlenamelength};</code><br>
<!-- If/when somebody makes the page on arithmetic operations, mention that NUMBER can be an arithmetic operation as well
and link it. -->
<br>
{% highlight bash %}
${#VARIABLE}
@ -67,5 +69,9 @@ Example: <code>lastname=${middlename:$firstnamelength:$middlenamelength};</code>
This is equal to the length of the value of VARIABLE<br>
Example: <code>echo "your name has ${#name} characters";</code><br>
<br>
Paremeter expansions can also be nested, like this:
{% highlight bash %}
${input:?${INVALID_INPUT_ERR_MSG:-An unknown error occurred}}
{% endhighlight %}
<br>
Further reading: <a href="http://www.gnu.org/software/bash/manual/bashref.html#Shell-Parameter-Expansion">the bash reference manual</a>