edit bash_tricks

system/bash_tricks.md

@@ -12,6 +12,11 @@ See changes in a directory, as it changes:
 
 `watch -d ls *directory*`
 
+Or use the `-g` flag to exit once the output changes.
+This command will look at whether you're connected to the internet, and turn into a rainbow once the connection hits.
+
+> watch -g ip address && clear && ip address | lolcat
+
 ## Automatic Renaming
 
 There are a bunch of files:
@@ -34,17 +39,19 @@ done
 
 IFS is the field separator.  This is required to denote the different files as marked by a new line, and not the spaces.
 
+(Alternatively, just install `renameutils` and do `rename Column Alice *`)
+
 ## Arguments and Input
 
 The `rm' program takes arguments, but not `stdin' from a keyboard, and therefore programs cannot pipe results into rm.
-
+To fix this, use `xargs` to turn the stdin into an argument.
-That said, we can sometimes pipe into rm with `xargs rm' to turn the stdin into an argument.  For example, if we have a list of files called `list.txt' then we could use cat as so:
+For example, if we have a list of files called `list.txt' then we could use cat as so:
 
 ```bash
 cat list.txt | xargs rm
 ```
 
-... *However*, this wouldn't work if spaces were included, as rm would take everything literally.
+Of course if spaces are included in the file, you would have to account for that.
 
 ## Numbers
 
@@ -71,3 +78,22 @@ find . -type f -exec md5sum '{}' ';' | sort | uniq --all-repeated=separate -w 15
 ```bash
 cat /dev/urandom | tr -cd [:alnum:] | dd bs=1 count=200 status=none && echo
 ```
+
+## Temporary Working Directory
+
+Try something out in a random directory in `/tmp` so the files will be deleted when you next shut down.
+
+```bash
+mktemp -d
+```
+
+That gives you a random directory to mess about in.
+
+```bash
+   dir=$(mktemp -d)
+   for x in {A..Z}; do
+      fortune > "$dir"/chimpan-$x
+   done
+   cd $dir
+```
+