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- [轉貼]Bash Shell: Check File Exists or Not
- Bash Shell: Check File Exists or Not
by VIVEK GITE on APRIL 20, 2012 last updated APRIL 20, 2012
How do I test existence of a text file in bash running under Unix like operating systems?
You need to use the test command to check file types and compare values. The same command can be used to see if a file exist of not. The syntax is as follows:
test -e filename
[ -e filename ]
test -f filename
[ -f filename ]
The following command will tell if a text file called /etc/hosts exists or not using bash conditional execution :
[ -f /etc/hosts ] && echo "Found" || echo "Not found"
Sample outputs:
The same code can be converted to use with if..else..fi which allows to make choice based on the success or failure of a test command:
#!/bin/bash
file="/etc/hosts"
if [ -f "$file" ]
then
echo "$file found."
else
echo "$file not found."
fi
File test operators
The following operators returns true if file exists:
-b FILE
FILE exists and is block special
-c FILE
FILE exists and is character special
-d FILE
FILE exists and is a directory
-e FILE
FILE exists
-f FILE
FILE exists and is a regular file
-g FILE
FILE exists and is set-group-ID
-G FILE
FILE exists and is owned by the effective group ID
-h FILE
FILE exists and is a symbolic link (same as -L)
-k FILE
FILE exists and has its sticky bit set
-L FILE
FILE exists and is a symbolic link (same as -h)
-O FILE
FILE exists and is owned by the effective user ID
-p FILE
FILE exists and is a named pipe
-r FILE
FILE exists and read permission is granted
-s FILE
FILE exists and has a size greater than zero
-S FILE
FILE exists and is a socket
-t FD file descriptor FD is opened on a terminal
-u FILE
FILE exists and its set-user-ID bit is set
-w FILE
FILE exists and write permission is granted
-x FILE
FILE exists and execute (or search) permission is granted
The syntax is same (see File operators (attributes) comparisons for more info):
if [ operator FileName ]
then
echo "FileName - Found, take some action here"
else
echo "FileName - Not found, take some action here"
fi
原文出處：Bash Shell: Check File Exists or Not
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[轉貼]Find Out If File Exists With Conditional Expressions (冷日