I discussed about lsof and ps(process status) commands in the last blog post. I strongly recommend you to read earlier blogs for better understanding . If you find something missing, Please provide feedback in comment box so that I can take corrective action.
I will be using redirection wherever it requires.
- > Redirect output
- >> Redirect and append
- < Redirect input
- << Redirect input and append
- | Pipe
- tee Redirect to two objects . You may think it as Tee used in plumbing
Q: Standard Output i.e. stdout(FD=1) is Monitor screen , What can be Standard Input i.e. stdin(FD=0) ? …You know that
As we observed that the root filesystem itself has a number of utilities and libraries for supporting linux based applications. The next requirement is to understand the search options. The most frequently used commands are :
- locate to find files or directories
- locate test6
- find to search file is more powerful if you are aware of options
- find -type f -name test6 //Did you face any problem ? Try the command given below
- find -type f -name test6 2>/dev/null
- Did you notice the errors going to /dev/null ? Like black hole
- grep to search pattern in each file or standard input
- Even if you use grep , You can’t avoid error messages without redirecting stderr to /dev/null
- find -type f -name test6 | grep “day”
- Please refer to man or help for any specific requirement with these commands
Since Kernel takes care of resource management and the software architecture has flexibility to pick necessary utilities for Filesystem, There should be a method to design the entire filesystem from scratch. Following is the method to achieve the same :
- One can use dd(Data Definition) and mke2fs to create an etx2 file system
sanjay@sanjay-VirtualBox:~/linux_day5$ dd if=/dev/zero of=myfile1.img bs=1024 count=102400 102400+0 records in 102400+0 records out 104857600 bytes (105 MB, 100 MiB) copied, 0.248331 s, 422 MB/s sanjay@sanjay-VirtualBox:~/linux_day5$ mke2fs myfile1.img - sudo mount myfile1.img tmp/ -o loop
If we create partition table in the file image above, It will become virtual hard disk image. Loop device is a pseudo device which makes a filesystem appear as a block device. After mounting the filesystem, we can copy the required files inside this.
As I discussed earlier /dev directory nodes provide device access to user space application . However there is another directory /sys which provides device configuration and status specific information. /proc provides information related to kernel running status.
This particular article is discussed at Linux File System Creation
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