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Converts any number of seconds into days, hours, minutes and seconds.
sec2dhms() {
declare -i SS="$1"
D=$(( SS / 86400 ))
H=$(( SS % 86400 / 3600 ))
M=$(( SS % 3600 / 60 ))
S=$(( SS % 60 ))
[ "$D" -gt 0 ] && echo -n "${D}:"
[ "$H" -gt 0 ] && printf "%02g:" "$H"
printf "%02g:%02g\n" "$M" "$S"
}
Who needs a DNS server
Normally, if you su to another user from root and try to resume that other user's screen session, you will get an error like "Cannot open your terminal '/dev/pts/0' - please check." This is because the other user doesn't have permission for root's pty. You can get around this by running a "script" session as the new user, before trying to resume the screen session. Note you will have to execute each of the three commands separately, not all on the same line as shown here.
Credit: I found this at http://www.hjackson.org/blog/archives/2008/11/29/cannot-open-your-terminal-dev-pts-please-check.
After executing a command with multiple arguments like
cp ./temp/test.sh ~/prog/ifdown.sh
you can paste any argument of the previous command to the console, like
ls -l ALT+1+.
is equivalent to
ls -l ./temp/test.sh
ALT+0+. stands for command itself ('ls' in this case)
Simple ALT+. cycles through last arguments of previous commands.
Curl is not installed by default on many common distros anymore. wget always is :)
$ wget -qO- ifconfig.me/ip
Convert readable date/time with `date` command
Run the alias command, then issue
$ps aux | tail
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 default of 80.
The default for TAIL is to output the last 10 lines, this alias changes the default to output the last x lines instead, where x is the number of lines currently displayed on your terminal - 7. The -7 is there so that the top line displayed is the command you ran that used TAIL, 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. ( http://www.askapache.com/linux/bash-power-prompt.html )
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.
usage: sitepass MaStErPaSsWoRd example.com
description: An admittedly excessive amount of hashing, but this will give you a pretty secure password, It also eliminates repeated characters and deletes itself from your command history.
tr '!-~' 'P-~!-O' # this bit is rot47, kinda like rot13 but more nerdy
rev # this avoids the first few bytes of gzip payload, and the magic bytes.