On 19Mar2009 18:55, Daniel B. Thurman <dant@xxxxxxxxx> wrote:
> Cameron Simpson wrote:
>> Ok, but I strongly recommend you never us a regexp unquoted - the
>> necessary backslash nesting gets nasty real fast. A better way is like
>> this:
>> re='s/b/h/'
>> sed -e "$re"
[...]
>> The point here, unrelated to the pipe exit status issue, is to keep the
>> sed stuff easy to write and undamaged by shell substitution. [...]
>
> Another person sent me private email
> warning of the double-quotes, but thanks
> for your information, it is interesting!
>
> This is what I ended up doing, so please give
> your constructive critiques, if you so like?
Untested, but here is how I would write each of you code pieces were I doing
it myself:
> TRACKER="Tracker.log"
> SFILE="Bad_Hosts_File.txt"
> TFILE="Bad_Hosts_File_$$.txt"
tracker=Tracker.log
sfile=Bad_Hosts_File.txt
tfile=Bad_Hosts_File_$$.txt
Your quotes are unneeded here. Plenty of people find the "" marks and in
similar cases, to use ${foo} instead of $foo elsewhere, but I find the
syntactic noise annoying if there's no other necessity.
Also, you should never use UPPER CASE names for script local variables (i.e.
that are not to be exported). I give some background why here:
http://markmail.org/message/awimhb3nmu6ssvwp
> pat="EACC"
pat=EACC
> re1="-e '/$pat/s/^.*Received:\[from\s\+\(.*\)\s\+(.*/\1/'"
> re2="-e '/^.*cdkkt.com$/d'"
Note that this "$" should probably be backslashed. As it happens, $/ is
not a shell special variable, so it is left alone. However, has you used
$# or one of the others ($!, et al) there would have been substitution
done, mangling your sed code.
> rex="sed $re1 $re2"
I would strongly reommend putting this in a sed script file, perhaps
like this:
cat >sedf$$ <<X
/$pat/s/^.*Received:\[from\s\+\(.*\)\s\+(.*/\1/
/^.*cdkkt.com\$/d
X
rex="sed -f sedf$$"
Hmm, actually, maybe not. Maybe like this:
sedline="/$pat/s/^.*Received:\[from\s\+\(.*\)\s\+(.*/\1/; /^.*cdkkt.com\$/d"
and then:
sed -e "$sedline"
in your pipeline lower down.
> echo -en "\033[0;36m>> \033[0;35mExtracting data from:\n \
> [\033[0;34m${TRACKER}\033[0;35m and appending to\n \
> [\033[0;34m${TFILE}\033[0;35m]\033[0m"
I usually put escape sequences into their own variables for readbility,
like this:
http://www.cskk.ezoshosting.com/cs/rc/shell/colour_ansi
Then you can talk about ${tty_green}, ${tty_normal} etc in your text;
somewhat more readable. You can do even better than this, actually.
Since not all terminals use the ANSI colour escapes, it is better to use
tput, like this:
http://www.cskk.ezoshosting.com/cs/css/bin/with-colour
and then in your script:
esc_tracker=`with-colour green echo "$TRACKER"`
and then use ${esc_tracker} in messages. And so forth.
> out=$(grep "$pat" "${TRACKER}" | \
> eval "$rex" | sort -n | \
> uniq >> "${TFILE}"); ret="$?";
>
> if [ "$ret" -gt 0 ] || \
> [ "$PIPESTATUS[0]" -gt 0 ] || \
> [ "$PIPESTATUS[1]" -gt 0 ] || \
> [ "$PIPESTATUS[2]" -gt 0 ] || \
> [ "$PIPESTATUS[3]" -gt 0 ]; then
> echo -e " \033[0;31mFailed.\n \
> \033[0;35m-- ErrorStatus:<ret=$ret>,\
> PipeStatus:<$PIPESTATUS[@]>\n\
> -- out:<$out>\033[0m"
> echo -e "\033[0;31m>> \033[0;31m$PROG exited.\033[0m\n"
> exit 1
> fi
> echo -e " \033[0;32mDone.\033[0m";
>
> I guess the ugly part is the multiple $PIPESTATUS[n]
> in the if statement test block. but perhaps this is the best
> I can do?
Nah. You can do this:
if out=$(grep "$pat" "$tracker" | $rex | sort -un >>"$tfile")
then
case " $PIPESTATUS" in
*' '[1-9]*)
echo exit ok, but PIPESTATUS=$PIPESTATUS
;;
*)echo exit ok and PIPESTATUS all zeroes
;;
esac
else
echo exit not ok
fi
Um, you are aware that $out will always be empty? You have sent
standard out to the temp file. Standard error is not collected by back
ticks or $(); it will be displayed directly and not land in $out.
You probably need to go:
out=$(exec 2>&1; grep .... >>"$tfile")
An easy test is like this:
out=$(ls /no/such/file >>temp)
echo "out=[$out]"
versus:
out=$(exec 2>&1; ls /no/such/file >>temp)
echo "out=[$out]"
Cheers,
--
Cameron Simpson <cs@xxxxxxxxxx> DoD#743
http://www.cskk.ezoshosting.com/cs/
The aim of AI is to make computers act like the ones in the movies.
- Graham Mann
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