add time.c and some formatting of readmes

Author: fairclothjm

c/README.md

@@ -2,6 +2,13 @@
 
 Code snippets for C.
 
+## notes
+
+Build with:
+```
+gcc <file>.c -std=c99 -o <file>.out
+```
+
 
 ## todo
 

c/time.c

@@ -0,0 +1,24 @@
+#include <stdio.h>
+#include <time.h>
+
+// retrieve current time
+// format as string
+// write to standard output
+
+int main()
+{
+    time_t now;
+    struct tm *ts;
+    char buf[80];
+
+    // get current time
+    now = time(NULL);
+
+    // format and print the time
+    // "ddd yyyy-mm-dd hh:mm:ss zzz"
+    ts = localtime(&now);
+    strftime(buf, sizeof(buf), "%a %Y-%d-%d %H:%M:%S %Z", ts);
+    puts(buf);
+
+    return 0;
+}

go/modules.md

@@ -2,39 +2,39 @@
 
 ### create new module
 
-Make the current directory the root of a module
+Make the current directory the root of a module:
 ```
 go mod init example.com/hello
 ```
 
-List the current module and all its dependencies
+List the current module and all its dependencies:
 ```
 go list -m all
 ```
 
 ### module management
 
-Get a specific module version
+Get a specific module version:
 ```
 go get example.com/[email protected]
 ```
 
-Get a branch
+Get a branch:
 ```
 go get example.com/hello@<branch-name>
 ```
 
-Get a commit
+Get a commit:
 ```
 go get example.com/hello@<commit>
 ```
 
-Add missing and remove unused modules
+Add missing and remove unused modules:
 ```
 go mod tidy
 ```
 
-Explain why packages or modules are needed
+Explain why packages or modules are needed:
 ```
 go mod why -m <module-path>
 ```
@@ -48,12 +48,12 @@ Ref: [Defining Go Modules (Go & Versioning, Part 6)](https://research.swtch.com/
 
 #### usage
 
-Make a vendored copy of dependencies
+Make a vendored copy of dependencies:
 ```
 go mod vendor
 ```
 
-Build dependencies from the vendor directory
+Build dependencies from the vendor directory:
 ```
 go build -mod vendor
 ```

nmap.md

@@ -2,21 +2,21 @@
 
 ## usage examples
 
-The following examples assume a target of `192.168.0.0/24`.
-
+Flag to set timing template (higher is faster):
 ```
--T<0-5>: Set timing template (higher is faster)
+-T<0-5>
 ```
 
 ### OS scan
-Determine OS of hosts.
+
+Determine OS of hosts:
 ```
 nmap -O 192.168.0.0/24
 ```
 
 ### ping scan
-Determine hosts reachable via ping.
 
+Determine hosts reachable via ping:
 ```
 nmap -sn 192.168.0.0/24
 ```