ctrap script

#!/bin/bash
ctrap(){
echo -ne "\033]0;"puppet"\007"
}
if [ $# -eq 1 ];then
trap ctrap SIGINT
echo -ne "\033]0;"$1"\007"
ssh $1
ctrap
exit 0
fi
ssh $*

grantaccess.sh

#!/bin/sh

if [ $# -lt 4 ]; then
echo "syntax: $0 host user time 'reason'"
echo "e.g. grantaccess.sh '0am jan 10' 'reason why'"
exit 1
fi

ssh $1 usermod -U $2
ssh $1 chage -E -1 $2
echo "ssh $1 usermod -L $2 " | at $3
echo "ssh $1 skill -KILL -u $2" | at $3
echo `logname` granted $2 access on $1 till $3 - Reason Given:"$4" | mail -s "Access granted"

sed && awk one-liners

These guides are great. Thanks to all who compiled them.

Famous sed one-liners Explained, Part I
Famous sed one-liners Explained, Part II
Famous sed one-liners Explained, Part III

Famous awk one-liners Explained, Part I
Famous awk one-liners Explained, Part II
Famous awk one-liners Explained, Part III

Convert Windows CR/LF to Unix newlines

sed 's/.$//'

sed 's/^M$//'

Delete lines from a file by line number with sed

Today i decided to make a new monitoring tool, and I needed to make a list of all permutations of 3 in a set of 22. The set happens to be hostnames of a private Tor network. Order is important, as forming 3-hop circuits through Tor is sequential, which is why i need permutations instead of combination's.

22 * 21 * 20 = 9240 permutations

Crap, I'm not really up on my combinatorial number theory, I guess I'll have to hack it up.

First I used an excel plugin to generate all the permutations.

But this ended up giving me 1408 invalid permutations, because the mix of sets had 10647 results. I copied the results into a text file and counted the number of lines as well as obtained the line numbers of the invalid permutations using this script:
----------
#!/bin/sh

tornames=("tornode01" "tornode02" "tornode03" "tornode04" "tornode05" \
"tornode06" "tornode07" "tornode08" "tornode09" "tornode10" \
"tornode11" "tornode12" "tornode13" "tornode14" "tornode15" \
"tornode16" "tornode17" "tornode18" "tornode19" "tornode20" \
"tornode21" "tornode22")

for i in ${tornames[*]};
do
while read line; do echo $line|tr " " "\n"|grep $i |wc -l; done < ./vc_list.bak > ./lines.$i
grep -rn '3\|2' ./lines.$i | cut -d: -f1 > ./lines.$i.ln
done
----------

It saved a bunch of files for me as: lines.[hostname], containing a number on each line indicating the number of times the hostname appears on each line.
Then it grep'd out the lines with a 2 or a 3, asking grep to return the line number, and cut the line number from the output to a file named: lines.[hostname].ln

Then at the command line I did this:

# cat ./lines.*.ln > line.numbers.all
# sed 's/.*/&d/g' ./line.numbers.all > ./delete.sed
# sed -f delete.sed ./file.master >> file.trimmed

Using a sed delete file...finally I had my 9240 valid permutations:

# cat ./file.trimmed | wc
9240 27720 254520

Next I want to make this text list into an array that I can `source` into the monitoring script as an array.

# rsync ./file.trimmed ./perms_array.sh
sed -i -e 's/^\./perms_array.sh

Almost done, I just need to fill in the array number with another sed expression.

# sed = ./perms_array.sh | sed 'N; s/^// ; s/\nperms\[// ; s/^/perms\[/' > \
./perms_array.final.sh

and now to put quotes around the array value:

# sed -e 's/\=/\=\"/' < ./perms_array.final > ./perms_array.final.new && rsync ./perms_array.final.tmp ./perms_array.final
# sed -e 's/$/\"/' < ./perms_array.final > ./perms_array.final.new && rsync ./perms_array.final.tmp ./perms_array.final

here's what the file looks like:

perms[1]="tornode01 tornode02 tornode03"
perms[2]="tornode01 tornode04 tornode05"
perms[3]="tornode01 tornode06 tornode07"
...

Now I can move on to write an essentially simple script that performs the test of all possible virtual circuits.

oops

Today I was trying to move a file into the home directory of the current user, like this:

# mv /home/otheruser/somefile ~

Interestingly enough, after doing this for the last 15 years, I fat-fingered it like this:

# mv /home/otheruser/somefile !

CRAP!
Guess what, my file was deleted.
Btw, Mac OSX doesnt behave like this. I assume *BSD, Solaris and other high-quality systems dont as well. Pooor Linux.