Shell determines whether a folder or file exists

The folder does not exist and is created

if [!-d "/data/"];thenmkdir/dataelseecho "folder already exists" fi

File exists then delete

if [!-F "/data/filename"];thenecho "file does not exist" Elserm-rf/data/filenamefi

Determine if a folder exists

If [-d '/data/"];thenecho" folder exists "Elseecho" folder does not exist "fi

Determine if a file exists

If [-d '/data/test "];thenecho" file exists "Elseecho" file does not exist "fi

File comparison characters

-e filename  if filename exists, true  [-e/var/log/syslog]-d filename  if filename is directory, true  [-d/tmp/mydir]-f fi Lename  True if filename is a regular file  [-f/usr/bin/grep]-l filename  If filename is a symbolic link, true  [-l/usr/bin/grep]-r FileName  If filename is readable, true  [-r/var/log/syslog]-w filename  If filename is writable, true  [-w/var/mytmp.txt]- x filename  If filename is executable, true  [-l/usr/bin/grep]filename1-nt filename2  If filename1 is newer than filename2, true c15/>[/tmp/install/etc/services-nt/etc/services]filename1-ot filename2  If filename1 is older than filename2, then true  [/ Boot/bzimage-ot Arch/i386/boot/bzimage]

　　

　　

Shell determines whether a folder or file exists