问题
I write a scipt like this:
#!/bin/bash
while read line
do
echo line ${line}
pdbfile=${line}.pdb
echo pdbfile ${pdbfile}
done < myfile
The result is:
line pdb8mhtA
.pdbfile pdb8mhtA
While it is supposed to be
line pdb8mhtA
pdbfile pdb8mhtA.pdb
What's wrong with this? Why the string concatenation does not work? And why the strange dot at the beginning of the line?
I replace with pdbfile=${line}'.pdb'. That does not change the result.
回答1:
The "string goes to the beginning of the line" is symptomatic of a carriage return in your $line that you can among many other ways remove with a tr pipe to your file:
while IFS= read -r line
do
echo "line ${line}"
pdbfile=${line}.pdb
echo "pdbfile ${pdbfile}"
done < <(tr -d '\r' <file)
回答2:
I've tried your script and it works fine for me:
./testConcat
line pdb8mhtA
pdbfile pdb8mhtA.pdb
btw you could try to "preserve" the "."
while read line
do
echo line ${line}
pdbfile=${line}\.pdb
echo pdbfile ${pdbfile}
done < myfile
as you can see the result is the same
./testConcat
line pdb8mhtA
pdbfile pdb8mhtA.pdb
来源：https://stackoverflow.com/questions/41219148/shell-strange-string-concatenation-behavior