Added proc files such as /proc/meminfo, /proc/cmdline and commands like lsmod, modinfo, uptime

README.md

@@ -97,6 +97,8 @@ Notes:
 
 - Use `nohup` or `disown` if you want a background process to keep running forever.
 
+- Know how long the system is running. Use `uptime` or `w` command and note the value in the third field of first row. That tells the current uptime of the system.
+
 - Check what processes are listening via `netstat -lntp` or `ss -plat` (for TCP; add `-u` for UDP).
 
 - See also `lsof` for open sockets and files.
@@ -163,10 +165,6 @@ Notes:
 
 - For general searching through source or data files (more advanced than `grep -r`), use [`ag`](https://github.com/ggreer/the_silver_searcher).
 
-- To know the type of the file, use the eponymous file command. Like,
-$ file vm_qa.py 
-vm_qa.py: a /usr/bin/env python script text executable
-
 - To convert HTML to text: `lynx -dump -stdin`
 
 - For Markdown, HTML, and all kinds of document conversion, try [`pandoc`](http://pandoc.org/).
@@ -256,9 +254,9 @@ vm_qa.py: a /usr/bin/env python script text executable
 
 - Know how to connect to a running process with `gdb` and get its stack traces.
 
-- Use `/proc`. It's amazingly helpful sometimes when debugging live problems. Examples: `/proc/cpuinfo`, `/proc/xxx/cwd`, `/proc/xxx/exe`, `/proc/xxx/fd/`, `/proc/xxx/smaps`.
+- Use `/proc`. It's amazingly helpful sometimes when debugging live problems. Examples: `/proc/cpuinfo`, `/proc/meminfo`, `/proc/cmdline`, `/proc/xxx/cwd`, `/proc/xxx/exe`, `/proc/xxx/fd/`, `/proc/xxx/smaps` (Where xxx is used to denote process id or pid)
 
-- When debugging why something went wrong in the past, `sar` can be very helpful. It shows historic statistics on CPU, memory, network, etc.
+- When debugging why something went wrong in the past, `sar` can be very helpful. It shows historic statistics on CPU, memory, network, disk activites etc.
 
 - For deeper systems and performance analyses, look at `stap` ([SystemTap](https://sourceware.org/systemtap/wiki)), [`perf`](http://en.wikipedia.org/wiki/Perf_(Linux)), and [`sysdig`](https://github.com/draios/sysdig).
 
@@ -444,6 +442,10 @@ A few examples of piecing together commands:
 
 - `lshw`, `lscpu`, `lspci`, `lsusb`, `dmidecode`: hardware information, including CPU, BIOS, RAID, graphics, devices, etc.
 
+- `lsmod`: List the currently loaded kernel modules.
+
+- `modinfo`: Use `modinfo <module-name>` to get the details of a specific kernel module.
+
 - `fortune`, `ddate`, and `sl`: um, well, it depends on whether you consider steam locomotives and Zippy quotations "useful"