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Run the alias command, then issue
$ps aux | head
and resize your terminal window (putty/console/hyperterm/xterm/etc) then issue the same command and you'll understand.
$ ${LINES:-`tput lines 2>/dev/null||echo -n 12`}
Insructs the shell that if LINES is not set or null to use the output from `tput lines` ( ncurses based terminal access ) to get the number of lines in your terminal. But furthermore, in case that doesn't work either, it will default to using the deafault of 12 (-2 = 10).
The default for HEAD is to output the first 10 lines, this alias changes the default to output the first x lines instead, where x is the number of lines currently displayed on your terminal - 2. The -2 is there so that the top line displayed is the command you ran that used HEAD, ie the prompt.
Depending on whether your PS1 and/or PROMPT_COMMAND output more than 1 line (mine is 3) you will want to increase from -2. So with my prompt being the following, I need -7, or - 5 if I only want to display the commandline at the top. ( https://www.askapache.com/linux/bash-power-prompt/ )
275MB/748MB
[7995:7993 - 0:186] 06:26:49 Thu Apr 08 [askapache@n1-backbone5:/dev/pts/0 +1] ~
$
In most shells the LINES variable is created automatically at login and updated when the terminal is resized (28 linux, 23/20 others for SIGWINCH) to contain the number of vertical lines that can fit in your terminal window. Because the alias doesn't hard-code the current LINES but relys on the $LINES variable, this is a dynamic alias that will always work on a tty device.
Searches for dates on lines by themselves. Uses that date to prepend all rows that contain SEARCHSTRING with the date, until it reaches another line with a date by itself. This fixed an issue with a specific log export where there would be a date, followed by all of the entries for that date.
This will record the capture channel of your soundcard, directly encoded in Ogg Vorbis, in stereo at quality 5 (I'm using this to record live jam sessions from my line input). You can choose which device to capture (eg. line input, microphone or PCM output) with
$ alsamixer -V capture
You can do the same thing and live encode in MP3 or FLAC if you wish, just check FLAC and LAME man pages.
Handy for those times you need to paste a file path in an IDE or some other app.
sudo apt-get install xclip
Then, for convenience, alias xclip to 'xclip -selection c' so you can just do something like realpath . | xclip
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
Surround the first letter of what you are grepping with square brackets and you won't have to spawn a second instance of grep -v. You could also use an alias like this (albeit with sed):
alias psgrep='ps aux | grep $(echo $1 | sed "s/^\(.\)/[\1]/g")'
sed already has an option for editing files in place and making backup copies of the old file. -i will edit a file in place and if you give it an argument, it will make a backup file using that string as an extension.
just change the date following the -r flag, and/or the user name in the user== conditional statement, and substitute yms_web with the name of your module
just a bit simpler