[talks/lbs] Added compound commands section to shell slides

1 files changed, 40 insertions, 3 deletions

diff --git a/src/talks/linuxgraphy-by-strabo/index.md b/src/talks/linuxgraphy-by-strabo/index.md
index 10b2aea..7342ebf 100644
--- a/src/talks/linuxgraphy-by-strabo/index.md
+++ b/src/talks/linuxgraphy-by-strabo/index.md
@@ -894,7 +894,19 @@ Most modern shells support a lot of the more defying features of the [Bourne She
   + `#`: Everything between a # and the end of the line denotes a comment
   + `#!`: If on the first line of the file, is treated as a [shebang](https://en.wikipedia.org/wiki/Shebang_%28Unix%29), which specifies what interpreter to be used for the script
 
-- compound commands: Shells also often offer more advanced structured, with which to more easily write complex expressions
+- compound commands: Structures for flow control  
+  In all examples, `test-command` is any command (or combination with control operators), and logic is based on exit code.
+
+  + conditional
+
+    ```
+    if test-command ; then commands-if-true
+    elif test-command ; then commands-if-true
+    else commands-if-true
+    fi
+    ```
+
+    elif statements can appear multiple times, both elif and else are optional
 
 &&/slide
 
@@ -902,9 +914,34 @@ Most modern shells support a lot of the more defying features of the [Bourne She
 
 &&slide
 
-## 3.2. Files and directories
+-  
+    &&lineb1
 
-&&lineb1
+    ```
+    case word in (pattern | ...) commands-if-true ;; ... esac
+    ```
+
+    Where the beginning brace can be ommited.  
+    Patterns are according to [bash's pattern matching](https://www.gnu.org/savannah-checkouts/gnu/bash/manual/bash.html#Pattern-Matching)
+
+  + loops
+
+    ```
+    while test-command; do commands-if-true; done
+    ```
+
+    ```
+    for name in words...; do commands-if-true; done
+    ```
+    If `in words...` is ommited, positional arguments are used
+
+&&/slide
+
+
+
+&&slide
+
+## 3.2. Files and directories
 
 - `/bin`: main command programs (binaries), used by users
 - `/etc`: system configuration files