Commands by wytten12

Commands by wytten12 (4)

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Delete all but the last 1000 lines of file
This is sample output - yours may be different.
-2

ex -c '1,$-1000d' -c 'wq' file

wytten12 · 2017-01-10 16:22:57 15
Join lines and separate with spaces

Read vmargs.txt, which is a text file that could either be DOS-style (\r\n) or UNIX-style (\n) line endings and join the lines with a space separator. Can this be shortened/made more elegant? Show Sample Output
This is sample output - yours may be different.
```
(line1) (line2) (line3) ...
```
1

tr -d '\r' < vmargs.txt | tr '\n' ' '

wytten12 · 2016-12-31 18:20:03 20
Reports file systems with disk usage exceeding 90% on the specified host
This is sample output - yours may be different.
0

function df_func { local dfts=$(ssh $1 "df -lP | tail -n +2 | sed 's/%//'"); echo $dfts | awk '$5 > 90 {exit 1}' > /dev/null; if [ $? == 1 ]; then echo -n "$1 "; echo $dfts | awk '$5 > 90 {printf "%s %d%%\n", $6, $5}'; fi }

wytten12 · 2016-03-30 19:57:39 13
Use emacs in place of tail -f

Monitoring a log file with 'tail -f' is handy, but for emacs users monitoring the file with emacs is even better, because you can use all your familiar key bindings for copying regions, etc.
This is sample output - yours may be different.
0

function emon { emacs "$1" --eval '(auto-revert-tail-mode)' --eval '(setq buffer-read-only t)' --eval '(goto-char (point-max))' }

wytten12 · 2012-11-21 17:24:27 5

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Make a high definition VNC

-nohttpd don't run mini-httpd if VNC java applet is found -name change the name of the desktop, it's passed to xstartup script via $VNCDESKTOP, run different set of apps acording the name. -depth pixel depth in bits of the desktop, default is 16 -geometry size of the desktop, default is 1024x768

Get AWS temporary credentials ready to export based on a MFA virtual appliance

You might want to secure your AWS operations requiring to use a MFA token. But then to use API or tools, you need to pass credentials generated with a MFA token. This commands asks you for the MFA code and retrieves these credentials using AWS Cli. To print the exports, you can use: `awk '{ print "export AWS_ACCESS_KEY_ID=\"" $1 "\"\n" "export AWS_SECRET_ACCESS_KEY=\"" $2 "\"\n" "export AWS_SESSION_TOKEN=\"" $3 "\"" }'` You must adapt the command line to include: * $MFA_IDis ARN of the virtual MFA or serial number of the physical one * TTL for the credentials

Get all mac address

Get mac address listed for all interfaces.

remap Caps_Lock to Escape

autossh + ssh + screen = super rad perma-sessions

Only useful for really flakey connections (but im stuck with one for now). Though if youre in this situation ive found this to be a good way to run autossh and it does a pretty good job of detecting when the session is down and restarting. Combined with the -t and screen commands this pops you back into your working session lickety split w/ as few headaches as possible. And if autossh is a bit slow at detecting the downed ssh connection, just run this in another tab/terminal window to notify autossh that it should drop it and start over. Basically for when polling is too slow. kill -SIGUSR1 `pgrep autossh`

list block devices

Shows all block devices in a tree with descruptions of what they are.

m4a to mp3 conversion with ffmpeg and lame

A batch file version of the same command would be: for f in *.m4a; do ffmpeg -i "$f" -acodec libmp3lame -ab 256k "${f%.m4a}.mp3"; done

Watch how many tcp connections there are per state every two seconds.

slighty shorter

Display a block of text with AWK

I find this terribly useful for grepping through a file, looking for just a block of text. There's "grep -A # pattern file.txt" to see a specific number of lines following your pattern, but what if you want to see the whole block? Say, the output of "dmidecode" (as root): $ dmidecode | awk '/Battery/,/^$/' Will show me everything following the battery block up to the next block of text. Again, I find this extremely useful when I want to see whole blocks of text based on a pattern, and I don't care to see the rest of the data in output. This could be used against the '/etc/securetty/user' file on Unix to find the block of a specific user. It could be used against VirtualHosts or Directories on Apache to find specific definitions. The scenarios go on for any text formatted in a block fashion. Very handy.

Create a tar archive using 7z compression

Using 7z to create archives is OK, but when you use tar, you preserve all file-specific information such as ownership, perms, etc. If that's important to you, this is a better way to do it.

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