Paul Schmehl wrote: > I could do this in perl easily, but I'm trying to force myself to learn > shell scripting better. :-) > > I'm parsing a file to extract some elements from it, then writing the > results, embeded in long strings, into an output file. > > Here's the script: > > cat file.1 | cut -d',' -f9 | sort | uniq > file.nicks > > (read line; echo "alert ip \$HOME_NET any -> \$EXTERNAL_NET any > (msg:\"JOIN $line detected\"; classtype:trojan-activity; > content:\"JOIN\"; content:$line; sid:2000001; rev:1;)"; while read line; > do echo "alert ip \$HOME_NET any -> \$EXTERNAL_NET any (msg:\"JOIN $line > detected\"; classtype:trojan-activity; content:\"JOIN\"; content:$line; > sid:2000001; rev:1;)"; done) < file.nicks > file.rules > > The result is a file with a bunch of snort rules in it (I can't provide > the actual data because it's sensitive.) > > The rules look like this: > alert ip $HOME_NET any -> $EXTERNAL_NET any (msg:"JOIN "channel" > detected"; classtype:trojan-activity; content:"JOIN"; content:"channel"; > sid:2000001; rev:1;) > alert ip $HOME_NET any -> $EXTERNAL_NET any (msg:"JOIN "channel2" > detected"; classtype:trojan-activity; content:"JOIN"; > content:"channel2"; sid:2000001; rev:1;) > > Once this file is created (or ideally *while* it's being created!) I > need to increment the sid numbers. The first one is 2000001. The > second needs to be 2000002, and so forth. I don't know the total > number of lines ahead of time, but it's easy enough to get after the > file is created. (wc -l file.rules | awk '{print $1}') > > Is there a way to do this in shell scripting? In perl I'd use a for > loop and vars, but I'm not sure how to solve this problem in shell > scripting. > > In pseudo code I would do: > > COUNT=`wc -l file.rules | awk '{print $1}'` > LAST_SID=$((2000000 + COUNT)) > for (i=2000001; i >= ${LAST_SID}; i++) { > sed 's/2000001/${i}/g < file.rules > rules.new' > } >
for i in `jot $COUNT 2000001`; do # foo bar done -- Pietro Cerutti PGP Public Key: http://gahr.ch/pgp
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