Monday, 31 March 2014

Bash File Testing

-b filenameBlock special file
-c filenameSpecial character file
-d directorynameCheck for directory existence
-e filenameCheck for file existence
-f filenameCheck for regular file existence not a directory
-G filenameCheck if file exists and is owned by effective group ID.
-g filenametrue if file exists and is set-group-id.
-k filenameSticky bit
-L filenameSymbolic link
-O filenameTrue if file exists and is owned by the effective user id.
-r filenameCheck if file is a readable
-S filenameCheck if file is socket
-s filenameCheck if file is nonzero size
-u filenameCheck if file set-ser-id bit is set
-w filenameCheck if file is writable
-x filenameCheck if file is executable



if [ -e $file ]; then

echo "File exists"

echo "File does not exists"

Similarly for example we can use while loop to check if file does not exists. This script will sleep until file does exists. Note bash negator "!" which negates the -e option.

while [ ! -e myfile ]; do

# Sleep until file does exists/is created

sleep 1


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