iostat service time (svctm) rule of thumb
iostat service time is a very useful metric when analyzing disk performance and finding bottlenecks service time is essentially the inverse of IOPs so if an operation takes 1ms to service, thenRead More…
Bash convert seconds to human readable
function displaytime { local T=$1 local D=$((T/60/60/24)) local H=$((T/60/60%24)) local M=$((T/60%60)) local S=$((T%60)) (( $D > 0 )) && printf ‘%d days ‘ $D (( $H > 0 )) && printf ‘%dRead More…
Wrong Port Connected Check With ifconfig
We need to run ifconfig and look for the status line. Remember this about ifconfig output: * if “status: active“, the port is linked up and sending traffic (now you just needRead More…
Grepping Thru All Rotated Logs
If your system gzips and rotates your logs. You can use this trick to search thru all of them. # zgrep -i — “SEARCHTERM” $(ls -1Str /var/log/messages*) Another way # zgrep -iRead More…
Find UPNP devices on your network – ex: ReadyDLNA or UPnP routers
Got info from here: https://stackoverflow.com/questions/18363833/how-can-i-list-upnp-server-renderer-in-command-line-console-mode-on-linux Get the Upnp test tools # apt-get install gupnp-tools Example 1: Find all Upnp devices (note their target names start with urn:…. It will hint at what service itRead More…
bash simple variable substitution
You can use bash to do simple substitutions of variables, just like you can with sed. The bash trick turns out to take up less characters (bytes). Lets set some variable VAR1="thisRead More…
Bash scripting dealing with any characters in strings or filenames
Imagine a file list, list.txt, like this one image1.jpg image2.jpg image3.jpg Naturally you could deal with it like so cat list.txt | while read i; do FILE="$i" dosomething "$FILE" done Or justRead More…
Repeat Command Until Success – recursive method – rrsync, repeat, repeatrecurse
Here I show you how to repeat a command until it finishes successfully. This should only be done with programs that support resume and also have legit exit codes (or else theyRead More…
FreeBSD – Show info about running process – SIGINFO
When you are running a command hit Control-T anytime, its very useful when a command looks stuck. It causes the kernel to spit out a line similar to the following: load: 0.69Read More…
Enable Mouse Scrolling with Screen (tested in Putty)
Screen the app that can split screens like so, is not too intuitive when it comes to scrolling thru your bash shell. Notice where the cursor is in the diagram below, itsRead More…