Shell Programming and Scripting

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.

Code:

FILE = 'basename $1'

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".

Code:

BANK = 'dirname $1'

the above command will remove the filename and assign path of file to BANK.
BANK will be "/abc/dir1/dir2/"

Code:

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

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