linux cheat sheet

# resources
ps -eo size,rss,pid,user,comm --sort -rss | head -n 30
ps -eo size,rss,pcpu,pid,user,comm --sort -pcpu | head -n 30

# memstat
atop -L160 1 1 | grep MEM

# caches

# chmod directories

# awk epoch to timestamp in logs
awk '{a = strftime("%F %T", $1); $1 = "" ; print a" "$0}'

# safe file delete

# some magic in resolv.conf

# default browser ( set default apps )
xdg-mime default firefox.desktop x-scheme-handler/http
xdg-mime default firefox.desktop x-scheme-handler/https

# keyboard
setxkbmap -layout us,ru -option grp:toggle

# qt crutch
export QT_GRAPHICSSYSTEM=native | raster | opengl

# swap usage by pid

# sqlite

# get url
wget -qO- http://foo/response
wget -qO- http://bar/api/json/response | python -m json.tool
wget -qO- http://bar/api/json/response | jq
wget -qO- http://bar/api/json/response | jq '.[] | select((.k_1 == 1) or (.k_2 == 2)) | "k1:\(.k_1) k2:\(.k_2)"'

# ssh/sshfs
sshfs -o reconnect -o auto_unmount 192.168.5.5:/mnt/data/usorted/ ~/sshfs/unsorted/


to remember

source

CLUSTERFUCK

Military term for an operation in which multiple things have gone wrong. Related to "SNAFU" (Situation Normal, All Fucked Up") and "FUBAR" (Fucked Up Beyond All Repair).

In radio communication or polite conversation (i.e. with a very senior officer with whom you have no prior experience) the term "clusterfuck" will often be replaced by the NATO phonetic acronym "Charlie Foxtrot."

Wonderful!

Bill Gates: “So, how’s heaven, Steve?”
Steve Jobs: “Great! It just doesn’t have any wall or fence.”
Bill Gates: “So…?”
Steve Jobs: “So, we don’t need any Windows and Gates. I’m sorry, Bill, I didn’t mean to offend you.”
Bill Gates: “It’s ok Steve, but I heard a rumor.”
Steve Jobs: “Oh, what rumor?”
Bill Gates: “That nobody is allowed to touch Apple there, and there are no Jobs in heaven.”
Steve Jobs : “Oh no, definitely there are, but only no–pay Jobs. Therefore definitely no Bill in heaven as everything will be provided free….”

How to chmod all directories except files (recursively)

source


find /path/to/base/dir -type d -print0 | xargs -0 chmod 755
find /path/to/base/dir -type f -print0 | xargs -0 chmod 644

PHP vs Python, ru only

Если вы решили перейти с PHP на Python

Web-разработка на Python глазами PHP-программиста

Delete file safe

shred -vuzn 5 /path/to/file

Cisco AIR LAP-1141 to AIR AP-1141, converting AP from CAPWAP to autonomous

Cisco AIR LAP-1141 - Lightweight Access Point (L letter before AP) controller-based (WLC)
Cisco AIR AP-1141 - Standalone (Autonomous) Access Point

I have at work two Cisco AP-1141. Thats great wireless stations and i like how it works. Few days ago we bought two more. But by mistake new access points were LAP. I dont have Cisco wireless controller at work, its very expensive and useless for us. So i was faced with task of reconfigure LAP 1141 to AP 1141. After searching some time i found that my task can be solved by changing IOS image on device.

First of all, i needed standalone AP IOS image archive. If you has original Cisco image for standalone AP downloaded from cisco.com thats greate. I did not have it. So i download it from my access point. To store image I use tftp server.

1. Setup TFTP server
I'm using Arch linux on laptop so config file for Arch(from official wiki)
I added only -c in ExecStart to allow create new files when uploading

*TFTP server configuration has been moved to /etc/conf.d/tftpd. Please update /etc/conf.d/tftpd and remove /etc/systemd/system/tftpd.service

/etc/systemd/system/tftpd.service
[Unit]
Description=hpa's original TFTP daemon

[Service]
ExecStart=/usr/bin/in.tftpd -c -s /srv/tftp/
StandardInput=socket
StandardOutput=inherit
StandardError=journal


/etc/conf.d/tftpd
TFTPD_ARGS="-c -v -s /srv/tftp/"


2. Uploading image archive to tftp (Cisco manual)
archive upload-sw tftp://10.1.1.64/c1140-k9w7-mx.124-21a.JA1.tar


3. When upload finished, everithing like here, connect to LAP Cisco device and run commands:

debug capwap con cli
conf t
boot manual
reload

After device reboot you should see the ap: prompt. If you issue a set command you'll see a few variables that you can change.

set IP_ADDR 10.1.1.21
set NETMASK 255.255.255.0
set DEFAULT_ROUTER 10.1.1.1
tftp_init
ether_init
flash_init
tar -xtract tftp://10.1.1.64/c1140-k9w7-mx.124-21a.JA1.tar flash:
set BOOT flash:/c1140-k9w7-mx.124-21a.JA1/c1140-k9w7-mx.124-21a.JA1
set MANUAL_BOOT no
set MODE_BUTTON yes
set
boot


After boot command device will boot uploaded image, and here we go, Cisco AIR AP-1141 stanbalone autonomous access point

Have fun ;)

IOS images:
*.k9w7.* - autonomous IOS
*.k9w8.* - full lightweight IOS (this is what is bundled in the WLC .aes image, and is factory installed on "mesh" APs)
*.rcvk9w8.* - lightweight recovery image - this is factory installed on lightweight APs, unless a "mesh" image is specified; it lacks radio firmware