I want to check whether if a file is a zero byte.
in if else condition
Which option should I use?
is it
-s
or
-z -- is this a valid option
Cannot find that in unix man for IF
Solution:
I always use -s ...
*if [[ -s /x/y/z/file ]]; then*
* ...*
*fi*
Always works.
or
See man page of bash(see below)
-s file
True if file exists and has a size greater than zero.
-z string
True if the length of string is zero.
-s for file size
-z for string size
or
You can man test instead of if
-s file True if file exists and has a size
greater than zero.
-f file True if file exists and is a regular
file. Alternatively, if /usr/bin/sh
users specify /usr/ucb before
/usr/bin in their PATH environment
variable, then test will return true
File exists and is zero byte
if [[ -f $file ]] && [[ ! -s $file ]]; then
echo "File is empty" ;
fi
