Variables overwriting text problem with "echo" in Bash
I use OS X 10.6.5, Bash.
When I run this:
echo $IP; echo of; echo $IPLINES
I get this output:
219.80.4.150:3128
of
1108
When I run this:
echo $IP of $IPLINES
I get this output:
of 1108.150:3128
I expected to get:
219.80.4.150:3128 of 1108
What would cause the distorted output I am getting?
The actual script is this:
#!/bin/bash
IPLINES=`cat a.txt | wc -l | awk '{print $1}'`
if [ $IPLINES > 1 ]; then
LINE=`expr $RANDOM % $IPLINES + 1`
IP=`head -$LINE a.txt | t开发者_Go百科ail -1`
sed -e "${LINE}d" -i .b a.txt
echo $IP of $IPLINES
fi
A wild guess here: you are extracting the IP variable from a .txt file -- if that's a Windows file, or is encoded Windows-style, lines end with \r\n
. You take the newline away, but what if there's a \r
in it that's making you go back to the beginning of the line?
Quick dirty fix with no questions asked: use echo -n
, it supresses the newline at the end of the echoed text.
echo -n $IP; echo -n of; echo -n $IPLINES
If the problem persists, it's probably what I said above. Try right-trimming $IP
.
EDIT: didn't see the OSX part, sorry. In OSX, lines end with \r
-- that must be the issue.
It would appear that there is a carriage return (\r
) at the end of $IP
.
精彩评论