Could someone please tell me what {} mean when they surround a variable?

For instance,

$FILE = 'basename $1' //what is passed into this script
$BANK = 'dirname $1'
$INFILE = ${FILE}.${BANK}.$$

What does $INFILE contain after this assignment?

Please let me know
Thanks
G

See below ....

$vi a.sh
ab=$(pwd)
echo " "
echo "Current working directory is $ab"
FILE=$(basename $ab)
echo "FILE returns $FILE "
echo " "
ab=$(pwd)
echo "Current working directory is $ab"
BANK=$(dirname $ab)
echo "BANK returns $BANK"
echo " "

INFILE=${FILE}.${BANK}.$$
echo $INFILE


dam@athena:~$ ./a.sh

Current working directory is /home/dam
FILE returns dam

Current working directory is /home/dam
BANK returns /home

dam./home.11937




Not sure what you are trying to achieve...

I think what you probably wanted was

/home/dam.11937

{} is used for building strings.
the above line of code is taking first parameter passed to this script as argument.what basename command will do here is if you have given the filename with path like /abc/dir1/dir2/filename then the
Value of FILE that is $FILE will have value "filename".
the above command will remove the filename and assign path of file to BANK.
BANK will be "/abc/dir1/dir2/"
Now the INFILE will have value "filename./abc/dir1/dir2/.3456"
here $$ gives the process id. in unix each command will run as a process and generates id.and value of $$ may differ in each run.

Wow does this sound like a homework question.

What do you notice:

THIS=that
$ echo $THIS1
$ echo ${THIS}1

#!/bin/bash
X=ABC
echo "$Xabc"

THis gives no output. What went wrong ? The answer is that the shell thought that we were asking for the variable Xabc, which is uninitialised. The way to deal with this is to put braces around X to seperate it from the other characters. The following gives the desired result:
#!/bin/bash
X=ABC
echo "${X}abc"

------------------

I think that it will clear your doubt.
still you are not getting ...pls give full details so that we can give a solution of same

Thanks
Ckanth