I have the following line in my unix script file:
if [[ -f $DIR1/$FILE1 ] -a [ -f $DIR1/$FILE2 ]]; then
As clear the line checks for existence of two files in a directory and if both the files are present, some logic will be executed.
However, on running the script I am getting the following error on above line:
test_script: line 30: syntax error at line 54: `]' unexpected
line 54 is where above line is present.
What does this error mean ? Where am I wrong ?
Thanks for reading!
For the most common shells at least, [] are not like parentheses in C where you use then to group subexpressions.
What you need is something like (for bash):
if [[ -f $DIR1/$FILE1 && -f $DIR1/$FILE2 ]]; then
If you want help with a specific (non-bash) shell, you should let us know which one you're using.
There is no need of [] with -f.
if [ -f $DIR1/$FILE1 -a -f $DIR1/$FILE2 ]; then
Output:
shadyabhi@archlinux /tmp $ touch foo;touch foo2
shadyabhi@archlinux /tmp $ if [ -f "foo" -a -f "foo2" ]; then echo "Hello"; fi
Hello
shadyabhi@archlinux /tmp $
It's interesting that there are multiple answers explaining the subtle differences between [ and [[, but for some reason our culture seems to discourage people from providing the obvious solution. Stop using '[' entirely. Instead of '[', use test:
if test -f $DIR1/$FILE1 && test -f $DIR1/$FILE2; then
Test is cleaner syntax than '[', which requires a final ']' argument and continually confuses people into thinking that the brackets are part of the language. '[[' is not portable and confuses people who don't realize that many shells provide extra functionality that is non-standard. There is a case to be made that [[ can be more efficient than [, but if run-time performance is a problem in your shell, you probably shouldn't be solving the problem in sh.
You had extra [ and ]
if [ -f $DIR1/$FILE1 -a -f $DIR1/$FILE2 ]; then
Basically, you were mixing two syntax that aim to do the same thing: namely [ ] and [[ ]]. The former is more portable but the latter is more powerful; although the majority of shells you would come across do support [[ ]].
But better still is the following since you are already using the [[ ]] construct
if [[ -f $DIR1/$FILE1 && -f $DIR1/$FILE2 ]]; then
As @paxdiablo stated, you can use it this way:
if -f $DIR1/$FILE1 && -f $DIR1/$FILE2 ; then
or you can use it this way:
if -f $DIR1/$FILE || -f $DIR1/$FILE2 ;
