Add slightly more information to the README

1 files changed, 40 insertions, 4 deletions

diff --git a/README.md b/README.md
index a9a1943..b6f011a 100644
--- a/README.md
+++ b/README.md
@@ -4,21 +4,57 @@ Record the memory usage of a process over time.
 
 # How to use MSTAT
 
+```text
+usage: mstat [OPTIONS] [-p PID] | {PROGRAM... ARGS}
+-c        clobber 'PID#.mstat' if it exists
+-h        this help message
+-o DIR    path to output directory (must exist)
+-p PID    process id to monitor
+-s RATE   samples per second (default: 1.00)
+-v        increased verbosity
+```
+
+## Monitor an existing process
+
+```shell
+$ mstat -p 12345
+PID: 12345
+Samples per second: 1.00
+(interrupt with ctrl-c...)
+```
+
+## Monitor a new process
+
 ```shell
-mstat <pid_here>
+$ mstat -s 10000 free
+PID: 12345 
+Samples per second: 10000.00
+(interrupt with ctrl-c...)
+               total        used        free      shared  buff/cache   available
+Mem:        28455904     8951836    10728332      476032     8775736    18596172
+Swap:       16777212           0    16777212
+pid 148257 returned 0
+data written: 12345.mstat
 ```
 
 ## Plotting
 
-Requires `gnuplot` to be installed
+Requires `gnuplot` to be installed.
+- Debian / Ubuntu
+  - `apt update && apt install gnuplot`
+- Fedora / RHEL
+  - `yum install gnuplot`
+- Arch Linux
+  - `pacman -S gnuplot`
+
 
 ```shell
-mstat_plot <pid_here>.mstat
+$ mstat_plot 12345.mstat
 ```
 
 ## CSV export
 
 ```shell
-mstat_export <pid_here>.mstat > data.csv
+$ mstat_export 12345.mstat > 12345.csv
 ```