Wednesday, 27. May 2009, 09:28:02
bash, marginal hacks, unix, hack
...
The bash(1) shell has some sadly underestimated features.
Most of shell users are aware of the existence of the so-called "here documents":
$ # create text file
$ cat > file.txt <<!
My username is $LOGNAME and my "home" directory is $HOME.
The quick brown fox...
!
$ #display the file content
$ cat file.txt
My name is unefunge and my "home" directory is /home/unefunge
The quick brown fox...
$
But did you know there's also "here string"?
$ # let's rot13
$ tr "a-z" "n-za-m" <<<"onfu ebpxf"
bash rocks
$
.. or, a bit more practical:
$ echo $HOME
/export/home/homer
$ BARTS_HOME=$(sed -e 's/homer/bart/' <<< "$HOME")
$ echo $BARTS_HOME
/export/home/bart
Wednesday, 20. May 2009, 16:13:33
snobol4, shell, marginal hacks, hack
...
As if just using Snobol4 wasn't scary enough:
$ cat spot
#! /bin/bash
snobol4 -b <(echo "$(basename $0) $@;end")
$ spot output = '":"' input '":"' :s\(spot\)
test
:test:
xyzzy
:xyzzy:
^D
$
Friday, 15. May 2009, 12:01:50
ruler, marginal hacks, terminal, hack
...
There are days your job description could be reduced to just "counting chars"...
function ruler() {
for ((x=1;x<$COLUMNS;x++));do
[[ $((x % 10)) -eq 0 ]]&&echo -n "|"||echo -n ".";
done;echo
}
export PROMPT_COMMAND=ruler
Friday, 15. May 2009, 11:49:14
marginal hacks, terminal, hack, animation
...
Don't ask me why did I program it ;-)
#! /bin/bash
trap "clear" 0 3 9 15
put() { tput cup $1 $2; echo -n "$3"; }
set -a X Y DX DY SHAPE
set -i i q
W=$((COLUMNS-2))
H=$((LINES-2))
for d in . o o o o o o o o o o @ ; do
q=$((q+1)); DX[q]=1; DY[q]=1; X[q]=$((q+4)); Y[q]=$((q+9)); SHAPE[q]="$d"
done
clear
while true ; do
put ${Y[1]} ${X[1]} ' '
for i in $(seq $q) ; do
[ ${X} -gt $W -o ${X} -lt 1 ] && DX=-${DX}
[ ${Y} -gt $H -o ${Y} -lt 1 ] && DY=-${DY}
X=$((X+DX))
Y=$((Y+DY))
put ${Y} ${X} ${SHAPE}
done
tput cup 0 0
usleep 50000
done
Have fun
WIDGETIZE