How do I check whether a file exists using Shell Script ?

[Praveen Hari]

How do I check whether a file exists in current directory and in a particular directory ?
e.g.
I like to see whether a file called a.txt exists in current directory ?
I like to see whether a file called a.txt exists in ..\temp directory ?

Thanks

[Steven E. Protter · Accepted solution]

if [ -f $file]
then
#take action because the file exists
fi

-s if the file is bigger than 0 bytes
-r if the file is readable
-w if the file is writable
-x if the file is executable

SEP