Commands by forcefsck

Commands by forcefsck (8)

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Find out the installation time of a linux system (when installed in a ext2/3/4 file system)

Find out the earliest installation time of a linux system by getting the / filesystem creation time. This example is only valid the os is installed on an ext2/3/4 filesystem.
This is sample output - yours may be different.
0

tune2fs -l $(df -P / | awk 'NR==2 {print $1}') | sed -n 's/^.*created: *//p'

forcefsck · 2012-05-31 12:12:35 0
encode/decode HTML entities

For reverse, there's asc2xml asc2xml < entitiesfile > utf8file They come as a part of the html-xml-utils debian package. PS. Tried to submit sample data, but the site autoconverted the non ascii to html entities. So a bit of imagination is needed. Show Sample Output
This is sample output - yours may be different.
```
$ echo "foo somegreekchars bar" | xml2asc
foo &#945;&#946;&#947;&#948; bar

$ echo "foo &#945;&#946;&#947;&#948; bar" | asc2xml 
foo somegreekchars bar
```
-3

xml2asc < inputfile > outputfile

forcefsck · 2011-02-23 12:22:18 1
Rename files in a directory in an edited list fashion

just an alternative to #7818 Show Sample Output
This is sample output - yours may be different.
```
Rename file: 1one
To: 1one.txt
`1one' -> `1one.txt'
Rename file: 2two
To: one plus one
`2two' -> `one plus one'
Rename file: 3three
To: 3three
Rename file: 4four
To: 2 x 2
`4four' -> `2 x 2'
Rename file: 5five
To: 5five.avi
`5five' -> `5five.avi'
```
0

exec 3<&0; ls -1N | while read a; do echo "Rename file: $a"; read -e -i "$a" -p "To: " b <&3 ; [ "$a" == "$b" ] || mv -vi "$a" "$b"; done

forcefsck · 2011-02-08 21:21:39 0
Display any udp/tcp connections by process name or by process id

Where COMMAND is the process(es) name. I prefer to get all states but you may add ESTABLISHED in the grep regex. lsof -c apache2 | egrep -o 'TCP.*ESTABLISHED.*$' -nP flags are optional and UDP is irrelevant for established connections Similar but using the process id: lsof -nP -p PID | egrep -o '(TCP|UDP).*$' Show Sample Output
This is sample output - yours may be different.
```
$ lsof -nP -c apache2 | egrep -o 'TCP.*$' | sort -u
TCP 192.168.0.2:443->192.168.0.136:3373 (ESTABLISHED)
TCP 192.168.0.2:443->192.168.0.137:11127 (ESTABLISHED)
TCP 192.168.0.2:443->192.168.0.137:11153 (ESTABLISHED)
TCP *:443 (LISTEN)
TCP *:80 (LISTEN)

$ lsof -p 17279|egrep -o '(TCP|UDP).*$'
TCP 127.0.0.1:32434 (LISTEN)
UDP *:32435 
```
0

lsof -nP -c COMMAND | egrep -o '(TCP|UDP).*$' | sort -u

forcefsck · 2011-01-25 12:04:13 0

network throughput test

On the machine acting like a server, run: iperf -s On the machine acting like a client, run: iperf -c ip.add.re.ss where ip.add.re.ss is the ip or hostname of the server. Show Sample Output

iperf -s

forcefsck · 2011-01-24 07:58:38 1

String to binary

Cool but useless. Show Sample Output
This is sample output - yours may be different.
```
perl -nle 'printf "%0*v8b\n"," ",$_;'
hello
01101000 01100101 01101100 01101100 01101111
world
01110111 01101111 01110010 01101100 01100100
!
00100001
```
6

perl -nle 'printf "%0*v8b\n"," ",$_;'

forcefsck · 2011-01-21 09:20:54 2
tcptraceroute alternative for udp packets

-T = traceroute -V = verbose --tr-stop = exit when target is reached -n = don't do reverse lookups (faster) -2 = udp -p 53 = destination port 53 (dns), change to your needs Useful when trying to debug a network with complex routing rules and/or multiple gateways.
This is sample output - yours may be different.
0

sudo hping3 -TV --tr-stop -n -2 -p 53 ns1.server.tld

forcefsck · 2011-01-14 10:12:37 0
Generate random valid mac addresses

Shorter and more straightforward. Also in perl: perl -e 'print join(":", map { sprintf "%0.2X",rand(256) }(1..6))."\n"'
This is sample output - yours may be different.
2

for i in {1..6}; do printf "%0.2X:" $[ $RANDOM % 0x100 ]; done | sed 's/:$/\n/'

forcefsck · 2010-12-07 19:26:58 0

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Access folder "-"

If you try to access cd - you go to the last folder you were in.

Getting information about model no. of computer

This command gives a model information of a computer. Also useful in determining the host is a VM machine or actual physical machine.

convert single digit to double digits

Uses 'rename' to pad zeros in front of first existing number in each filename. The "--" is not required, but it will prevent errors on filenames which start with "-". You can change the "2d" to any number you want, equaling the total numeric output: aka, 4d = ????, 8d = ????????, etc. I setup a handful of handy functions to this effect (because I couldn't figure out how to insert a var for the value) in the form of 'padnum?', such as: padnum5 () { /usr/bin/rename 's/\d+/sprintf("%05d",$&)/e' -- $@ } Which would change a file "foo-1.txt" to "foo-00001.txt"

Convert IP octets to HEX with no dots.

Converts IP octets to hex using printf command. Useful for generating pxeboot aliases in the pxelinux.cfg folder.

List hostnames of all IPs

Fetch the Gateway Ip Address

Better use iproute2 !

Using PIPEs, Execute a command, convert output to .png file, upload file to imgur.com, then returning the address of the .png.

imgur < /etc/issue % Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 100 2360 0 635 100 1725 1027 2792 --:--:-- --:--:-- --:--:-- 4058 http://i.imgur.com/bvbUD.png

Find the package that installed a command

Convert JSON to YAML

Requires installing json2yaml via npm: npm install -g json2yaml (can also pipe from stdin) Ref: https://www.npmjs.com/package/json2yaml

Remove old kernel packages

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