problem with while loop

Question

here is the script I wrote but it seems it has problem with while ! while suppose to compare the content of K with SDATE and while they are not equal go to the loop !

for d in \
 $(sed -nre 's/.*\[(..)\/(...)\/(....):(..:..:..) .*/\1 \2 \3 \4/p' thttpd.log | date +%s -f-);
do echo $d >s1; done

time=$(expr 60 \* 60 \* 24 \* 5)
EDATE=`tail -1 s1`
SDATE=$[$EDATE - $time]
time=$(expr 60 \* 60 \* 24 \* 5)
EDATE=`tail -1 s1`
SDATE=$[$EDATE - $time]
k=`tail -1 s1`
echo $k
echo $SDATE
while [$k -ne $SDATE](k and SDATE contain numbers)
 do
k=`tail -1 s1`
sed '1d' < s1 > tempfile
mv s1 s1.old
mv tempfile s1
echo $K| awk '{print strftime("%d/%m/%Y:%T",$1)}'|tee -a ass

done

Swiss · Accepted Answer · 2011-09-23 20:50:54Z

1

The problem is that you do not have spaces around [ or ]. Which causes BASH to parse the line incorrectly.

With the following line, BASH will attempt to run the program [$K, probably not what you are intending. while [$k -ne $SDATE]

What you need to have is the following:
while [ $k -ne $SDATE ]

answered Sep 23, 2011 at 20:50

Swiss

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Comments

Thomas · Accepted Answer · 2011-09-23 19:36:55Z

1

Try this:

while [[ $k != $SDATE ]]

answered Sep 23, 2011 at 19:36

Thomas

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6 Comments

Aida E Over a year ago

still has problem ! k is 1041454521 SDATE is 1041022521 and the error ./10: line 14: [[1041454521: command not found

ott-- Over a year ago

One bracket would be sufficient. The important thing is the space after [ and before ]. [ is another way to write "test", like: while test "$k" != "$DATE" ; do ...

Thomas Over a year ago

Hmm. I was always taught to use two brackets, because [[ is guaranteed to be a builtin, whereas [ might be an external program (and thus slower). And there were some other subtleties that I forgot.

Aida E Over a year ago

still has problem ! it's gonna kill me till run properly ! :((( 31/12/1969:16:00:00 ./10: line 14: [: -ne: unary operator expected it gives me the wrong date ! it's suppose to be 2003 not 1969

Thomas Over a year ago

I didn't write -ne anywhere.

|

LavaSlider · Accepted Answer · 2011-09-23 20:13:18Z

0

Ah, shell programming is so touchy...

k=0
while [ $k != 4 ]; do echo $k; k=`expr $k + 1`; done

Works and prints 0, 1, 2, 3 on separate lines as expected and this essentially looks like what you have except for spaces, newlines, and sources of values. Maybe it is a string versus value problem but I did not think shell variables had types.

I would try stripping what you have back until it works then add back what you want it to do.

answered Sep 23, 2011 at 20:13

LavaSlider

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1 Comment

LavaSlider Over a year ago

p.s. I also noticed on your third from last line (with the awk) it is $K instead of $k. Shell variables are case sensitive.

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