if exists bash; then echo 'Bash exists!' else echo 'Your system does not have Bash' fi 2018-12-1100 钨蜡唤喉晤 尝试使用: test -x filename 要么 [ -x filename ] 从条件表达式下的bash手册页: -x file True if file exists and is executable. 2018-12-1100 稼悸 如@lhunath建议的那样,...
For example, to test if the file/tmp/test.logexists, run the following command: test -f /tmp/test.txt The first line executes the test to see if the file exists. The second command,echo, displays the results. The result0means that the file exists, while1means no file was found. ech...
We are checking if the given file exists or not. Since there is the negation (!) operator and as the directory doesn’t exist, it will execute the then block of the code. This will enable the touch command to execute which will create the file. If we don't want the modification time...
file="./file" if [ -e $file ]; then echo "File exists" else echo "File does not exists" fi 1. 2. 3. 4. 5. 6. 7. 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 ne...
Now let’s perform a similar check,but with thetest [command: $if[ -x a.out ];thenecho"File is executable";elseecho"File is not executable";fiFile is executableCopy So, thetest‘sxflag proves if the file exists and is executable. ...
echo "---check the current process ,check the shell interpreter" long_name=$(ps ax|grep -E "^\s*$$";echo $?) echo $long_name # 简单处理,指定显示comm(仅显示可执行程序命令名: command name (only the executable name). Modifications to the command name will not be shown.) ...
-s FILE - True if the FILE exists and has nonzero size. -u FILE - True if the FILE exists and set-user-id (suid) flag is set. -w FILE - True if the FILE exists and is writable. -x FILE - True if the FILE exists and is executable.Conclusion...
But here, we used the which command, which is used to locate the executable file that would be executed if a command is run. It is also used to determine if the specified command exists. In the above code, the if statement checks if the wget command exists by running the command which...
-t fd True if file descriptor fd is open and refers to a terminal. -u file True if file exists and its set-user-id bit is set. -w file True if file exists and is writable. -x file True if file exists and is executable.
Finally, if you want to create an empty file, you can run the command: file.create("mynewfile.txt") How to Check if a Directory Exists Similarly, with the file.exists() we can work with the dir.exists() command for the directories. For example: if (dir.exists("my_tes...