Check These Out
grep searches through a file and prints out all the lines that match some pattern. Here, the pattern is some string that is known to be in the deleted file. The more specific this string can be, the better. The file being searched by grep (/dev/sda1) is the partition of the hard drive the deleted file used to reside in. The ?-a? flag tells grep to treat the hard drive partition, which is actually a binary file, as text. Since recovering the entire file would be nice instead of just the lines that are already known, context control is used. The flags ?-B 25 -A 100? tell grep to print out 25 lines before a match and 100 lines after a match. Be conservative with estimates on these numbers to ensure the entire file is included (when in doubt, guess bigger numbers). Excess data is easy to trim out of results, but if you find yourself with a truncated or incomplete file, you need to do this all over again. Finally, the ?> results.txt? instructs the computer to store the output of grep in a file called results.txt.
Source: http://spin.atomicobject.com/2010/08/18/undelete?utm_source=y-combinator&utm_medium=social-media&utm_campaign=technical
See man vmstat for information about the statistics.
This does the same thing without the timestamp:
$vmstat 5
Check whether hyperthreading is enabled or not.
a better solution as nproc
should work on all OS with awk
Opens a file or URL in the user's preferred application.
Using the sed -i (inline), you can replace the beginning of the first line of a file without redirecting the output to a temporary location.
Works on current directory, with built-in sorting.
PING
parameters
c 1 limits to 1 pinging attempt
q makes the command quiet (or silent mode)
/dev/null 2>&1 is to remove the display
&& echo ONLINE is executed if previous command is successful (return value 0)
|| echo OFFLINE is executed otherwise (return value of 1 if unreachable or 2 if you're offline yourself).
I personally use this command as an alias with a predefined machine name but there are at least 2 improvements that may be done.
Asking for the machine name or IP
Escaping the output so that it displays ONLINE in green and OFFLINE in red (for instance).
essentially the ruby one, but perhaps has a larger installed base
A shell function using perl to easily convert Unix-time to text.
Put in in your ~/.bashrc or equivalent.
Tested on Linux / Solaris Bourne, bash and zsh. using perl 5.6 and higher.
(Does not require GNU date like some other commands)
