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A nice way to interrupt a sleep with a signal.
'n' is a non-negative integer. Using 0 will expand to the name of the previous command.
unset PROMPT_COMMAND to disable.
The Linux /dev/full file simulates a "disk full" condition, and can be used to verify how a program handles this situation.
In particular, several programming language implementations do not print error diagnostics (nor exit with error status) when I/O errors like this occur, unless the programmer has taken additional steps. That is, simple code in these languages does not fail safely. In addition to Perl, C, C++, Tcl, and Lua (for some functions) also appear not to fail safely.
Removes ANSI color and end of line codes to the [{attr1};...;{attrn}m format.
Depending on the TERM, the terminfo version, ncurses version, etc.. you may be using a varied assortment of terminal escape codes. With this command you can easily find out exactly what is going on.. This is terminal escape zen!
$ ( 2>&2 strace -f -F -e write -s 1000 sh -c 'echo -e "initc\nis2\ncnorm\nrmso\nsgr0" | tput -S' 2>&1 ) | grep -o '"\\[^"]*"' --color=always
"\33]4;%p1%d;rgb:%p2%{255}%*%{1000}%/%2.2X/%p3%{255}%*%{1000}%/%2.2X/%p4%{255}%*%{1000}%/%2.2X\33\\\33[!p\33[?3;4l\33[4l\33>\33[?12l\33[?25h\33[27m\33(B\33[m"
Lets say you want to find out what you need to echo in order to get the text to blink..
$ echo -e "`tput blink`This will blink`tput sgr0` This wont"
Now you can use this function instead of calling tput (tput is much smarter for portable code because it works differently depending on the current TERM, and tput -T anyterm works too.) to turn that echo into a much faster executing code. tput queries files, opens files, etc.. but echo is very strait and narrow.
So now you can do this:
$ echo -e "\33[5mThis will blink\33(B\33[m This wont"
More at http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html
Not so much handy by itself, but very nice in shell scripts.
This makes you a handy ncurses based checklist. Much like terminal installers, just use the arrow keys and hit 'Space' to adjust the selections. Returns all selected tags as strings, with no newline at the end. So, your output will be something like:
"one" "two" "three" "four" "etc"
For those who prefer bash expansion over gratuitious typing:
$ whiptail --checklist "Simple checkbox menu" 12 35 3 $(echo {one,two,three,four}" '' 0"} )
Things to note:
The height must includes the outer border and padding: add 7 to however many items you want to show up at the same time.
If the status is 1, it will be selected by default. anything else, will be deselected.
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"
}
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"
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"
}
