Very strange things happened in the shell function

tpltp · #1 (**permalink**) 03-29-2008

Here is the script:

Code:

#!/bin/bash
#set -xv
RAWDATAFILE="temp1"
GOODDATAFILE="temp2"
FindSOS()
{
local NUM=0 #return value for the id of SOS
local cnt=1
if grep "EOS" $1
then
sed -e 's/.*<CobDate>//' -e 's/<\/.*//' <$1 > ${RAWDATAFILE}
sed -n -e '/EOS/,/SOS/ s/[0-9]*/&/p' <${RAWDATAFILE} >${GOODDATAFILE}
NUM=`more ${GOODDATAFILE} |sed -e 's/<EOS\/>//' -e 's/<SOS\/>//' |grep -v '^$'`
else            #The <SOS/> must be in the second line, the required EID is in the
                # first line
while read line
do
if [ ${cnt} -eq 1 ]; then
eval NUM=${line}
break
fi
cnt=$(($cnt+1))
done <$1

fi

echo $NUM
}

echo $NUM
exit 0

Here is the result:

Code:

./FindSOS.ksh sosofile
RAWDATAFILE="temp1"
+ RAWDATAFILE=temp1
GOODDATAFILE="temp2"
+ GOODDATAFILE=temp2
FindSOS()
{
local NUM=0 #return value for the id of SOS
local cnt=1
if grep "EOS" $1
then
sed -e 's/.*<CobDate>//' -e 's/<\/.*//' <$1 > ${RAWDATAFILE}
sed -n -e '/EOS/,/SOS/ s/[0-9]*/&/p' <${RAWDATAFILE} >${GOODDATAFILE}
NUM=`more ${GOODDATAFILE} |sed -e 's/<EOS\/>//' -e 's/<SOS\/>//' |grep -v '^$'`
else            #The <SOS/> must be in the second line, the required EID is in the
                # first line
while read line
do
if [ ${cnt} -eq 1 ]; then
eval NUM=${line}
break
fi
cnt=$(($cnt+1))
done <$1

fi

echo $NUM
}
id=`FindSOS $1`
FindSOS $1
++ FindSOS sosofile
++ local NUM=0
++ local cnt=1
++ grep EOS sosofile
++ sed -e 's/.*<CobDate>//' -e 's/<\/.*//'
++ sed -n -e '/EOS/,/SOS/ s/[0-9]*/&/p'
more ${GOODDATAFILE} |sed -e 's/<EOS\/>//' -e 's/<SOS\/>//' |grep -v '^$'
+++ more temp2
+++ sed -e 's/<EOS\/>//' -e 's/<SOS\/>//'
+++ grep -v '^$'
++ NUM=2080370166
++ echo 2080370166
+ id='<EOS/>
2080370166'
echo $id
+ echo '<EOS/>' 2080370166
<EOS/> 2080370166
exit 0
+ exit 0

I feel strange about that in the function, the NUM=2080370166, but why out of the function, id get the value, the value changes to "<EOS/> 2080370166"

Did I miss something here? Thank you

era · #2 (**permalink**) 03-30-2008

The output from FindSOS is the output of "grep EOS" plus the output of "echo $NUM".

Code:

if grep "EOS" "$1" >/dev/null  # note double quotes around $1, too

should fix it. (Or grep -q, if you have a fairly modern grep.)

The use of more | sed is an inventive way of avoiding a Useless Use of Cat Award (google for that), but I certainly would not recommend it.

As another stylistic issue, you could avoid the use of temporary files. Pipes are your friend and you are using them already. A file which only gets used once (by the immediately following command, too) can usually be turned into a pipe.

That while loop looks fairly mysterious, too. You will break out on the first line, correct? So you don't need the magic with $cnt and in fact it will never get executed. The idiomatic way to do that is head -n 1 anyway.

The funny | grep -v '^$' is superfluous too, as long as you are echoing $NUM unquoted, any blanks will be lost anyway.

Hope this helps.

tpltp · #3 (**permalink**) 03-30-2008

Thanks again, era. You are a master in this field! Your suggestion makes my script much easier. Keep learning from you...

More UNIX and Linux Forum Topics You Might Find Helpful
Thread	Thread Starter	Forum	Replies	Last Post
unable to format usb stick ?strange things happening as well!!!	wrapster	SUN Solaris	3	05-27-2008 08:59 AM
Strange problem with gettimeoftheday function	xyz123456	Linux	1	04-11-2008 05:13 AM
shell function help	Amresh Dubey	Shell Programming and Scripting	0	11-15-2007 04:16 AM
how to see function in shell	shriashishpatil	UNIX for Advanced & Expert Users	2	05-09-2006 11:35 PM
Gnome doing strange things.	Furtoes00	UNIX for Dummies Questions & Answers	5	03-18-2002 04:26 PM

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Display Modes	Rate This Thread
Switch to Linear Mode Hybrid Mode Switch to Threaded Mode	Rate This Thread:


	Powered by