diff options
Diffstat (limited to 'ult/handout.rst')
-rw-r--r-- | ult/handout.rst | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/ult/handout.rst b/ult/handout.rst index b72dbdc..5ef762a 100644 --- a/ult/handout.rst +++ b/ult/handout.rst @@ -1785,6 +1785,41 @@ So, these are all the paths that are searched, when looking to execute a command. If we put the results.sh script in one of these locations, we could simply run it, without using the ``./`` at the beginning. +Variables +--------- + +As expected, it is possible to define our own variables inside our shell +scripts. For example, + +:: + + name="FOSSEE" + +creates a new variable ``name`` whose value is ``FOSSEE``. To refer to this +variable, inside our shell script, we would refer to it, as ``$name``. +**NOTE** that there is no space around the ``=`` sign. + +:: + + ls $name* + +It is possible to store the output of a command in a variable, by enclosing +the command in back-quotes. + +:: + + count=`wc -l wonderland.txt` + +saves the number of lines in the file ``wonderland.txt`` in the variable +count. + +Comments +-------- + +The ``#`` character is used to comment out content from a shell script. +Anything that appears after the ``#`` character in a line, is ignored by +the bash shell. + Control structures and Operators ================================ @@ -1910,6 +1945,15 @@ dummy or a loop variable. It can then be used to refer to the element of the list that is currently being dealt with. We could, obviously, use something as lame as ``i`` in place of ``animal``. +To generate a range of numbers and iterate over them, we do the following. + +:: + + for i in {5..10} + do + echo $i + done + Now, we use a ``for`` loop to list the files that we are interested in. :: |