Commands by wejn

Commands by wejn (9)

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Print the IPv4 address of a given interface
This is sample output - yours may be different.
3

ip a s eth0 | awk -F'[/ ]+' '/inet[^6]/{print $3}'

wejn · 2014-10-13 18:33:38 10
dpkg: purge all packages matching some name

Recently in Debian Wheezy the dpkg command refuses to work with wildcards, so this is the one-liner alternative. (alternative to #13614)
This is sample output - yours may be different.
0

sudo dpkg -P $(dpkg -l yourPkgName* | awk '$2 ~ /yourPkgName.*/ && $1 ~ /.i/ {print $2}')

wejn · 2014-08-06 22:40:32 10
Extract domain from URl

Extracts 2nd-level domain part (or 3rd level, for co.* or com.*) from the URI's hostname. See sample output. Show Sample Output
This is sample output - yours may be different.
```
# not output itself but example mapping of ARGV[0] to output
http://test.example.com/something/here -> example.com
http://test.example.co.uk/something/else -> example.co.uk
http://test.example.com.cz/something/else -> example.com.cz
```
1

ruby -ruri -e 'u=URI(ARGV[0]).host.split("."); puts u[(u[-2] =~ /^com?$/ ? -3 : -2)..-1].join(".")' http://test.example.com

wejn · 2014-05-25 18:43:44 8
Displays the number of processes per state
This is sample output - yours may be different.
3

while true; do clear;awk '{a[$3]+=1};END{for(x in a){print x,a[x]}}' /proc/[0-9]*/stat; sleep 1; done

wejn · 2014-05-24 21:04:41 9
Extract shortcuts and hostnames from .ssh/config

Spits out table that shows your Host->HostName aliases in ~/.ssh/config
This is sample output - yours may be different.
3

awk '$1=="Host"{$1="";H=substr($0,2)};$1=="HostName"{print H,"$",$2}' ~/.ssh/config | column -s '$' -t

wejn · 2014-05-24 20:51:47 8
truncate deleted files from lsof

While the posted solution works, I'm a bit uneasy about the "%d" part. This would be hyper-correct approach: lsof|gawk '$4~/txt/{next};/REG.*$deleted$$/{sub(/.$/,"",$4);printf ">/proc/%s/fd/%s\n", $2,$4}' Oh, and you gotta pipe the result to sh if you want it to actually trim the files. ;) Btw, this approach also removes false negatives (OP's command skips any deleted files with "txt" in their name).
This is sample output - yours may be different.
1

lsof|gawk '$4~/txt/{next};/REG.*$deleted$$/{printf ">/proc/%s/fd/%d\n", $2,$4}'

wejn · 2014-03-11 10:40:32 13
Convert JSON to YAML

Show Sample Output
This is sample output - yours may be different.
```
Note: you need Ruby 1.9 or better
```
11

ruby -ryaml -rjson -e 'puts YAML.dump(JSON.parse(STDIN.read))' < file.json > file.yaml

wejn · 2013-04-24 07:20:37 128
Show number of connections per remote IP

Output contains also garbage (text parts from netstat's output) but it's good enough for quick check who's overloading your server.
This is sample output - yours may be different.
-1

netstat -antu | awk '{print $5}' | awk -F: '{print $1}' | sort | uniq -c | sort -n

wejn · 2013-04-08 19:46:41 10
Show header HTTP with tcpdump

This is a better way to do the "src X or dst X" filter; plus you might not want to bother with DNS lookups (-n).
This is sample output - yours may be different.
-1

tcpdump -s 1024 -l -A -n host 192.168.9.56

wejn · 2013-02-02 22:29:52 6

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split a multi-page PDF into separate files

Have to do this once per output file, because if device is 'pdfwrite', even if 'gs' sees '%d' in the OutputFile it still only creates one single output file. Embed it into a simple shell script if you want to split a document out into one file for every page.

Output Detailed Process Tree for any User

An easy function to get a process tree listing (very detailed) for all the processes of any gived user. This function is also in my http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html

the executable that started the currently running oracle databases and the ORACLE_HOME relative to each

get a list of currently running oracle dbs (identified by the pmon process) show the executable that spawned the process and show the ORACLE_HOME relative to the environment within which the process is running tailored to AIX (sed on linux behaves...differently) suggestions for a better way...please.

drop first column of output by piping to this

Searches $PATH for files using grep

Best to put it in a file somewhere in your path. (I call the file spath) #!/bin/bash IFS=:; find $PATH | grep $1 Usage: $ spath php

list file descriptors opened by a process

Useful for examining hostile processes (backdoors,proxies)

Get the Nth argument of the last command (handling spaces correctly)

Bash's history expansion character, "!", has many features, including "!:" for choosing a specific argument (or range of arguments) from the history. The gist is any number after !: is the number of the argument you want, with !:1 being the first argument and !:0 being the command. See the sample output for a few examples. For full details search for "^HISTORY EXPANSION" in the bash(1) man page. Note that this version improves on the previous function in that it handles arguments that include whitespace correctly.

Quick network status of machine

credit to tumblr engineering blog @ http://engineering.tumblr.com/

List only locally modified files with CVS

Open a manpage in the default (graphical) web browser

An easy alias for opening a manpage, nicely HTML formatted, in your set internet browser. If you get a "command exited with status 3" error you need to install groff.

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Commands by wejn (9)

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