updated README.md

- signed-off-by: trimstray <trimstray@gmail.com>

README.md

@@ -443,16 +443,16 @@ column -c3 -s " " -t | \
 sort -nr | nl |  head -n 20
 ```
 
-###### Empty a file (truncate to 0 size)
+###### Quickly backup a file
 
 ```bash
->filename
+cp filename{,.orig}
 ```
 
-###### Quickly backup a file
+###### Empty a file (truncate to 0 size)
 
 ```bash
-cp filename{,.orig}
+>filename
 ```
 
 ###### Delete all files in a folder that don't match a certain file extension
@@ -461,6 +461,16 @@ cp filename{,.orig}
 rm !(*.foo|*.bar|*.baz)
 ```
 
+###### Pass multi-line string to a file
+
+```bash
+# cat  >filename ... - overwrite file
+# cat >>filename ... - append to file
+cat > filename << __EOF__
+data data data
+__EOF__
+```
+
 ###### Edit a file on a remote host using vim
 
 ```bash
@@ -1039,6 +1049,12 @@ dd <dd_params> status=progress
 watch --interval 5 killall -USR1 dd
 ```
 
+###### Redirect output to a file with dd
+
+```bash
+echo "string" | dd of=filename
+```
+
 <a name="http-https"><b>HTTP/HTTPS</b></a>
 
 ##### Tool: [curl](https://curl.haxx.se)