Question

Linux Directories, File Properties, and the File System in C

Understanding Unix/Linux Programming

Your version of mv command

1. The mv command is more than just a wrapper around the rename system call. Write a version of mv that accepts two argument. The first argument must be the name of a file, and the second argument may be the name of a file or the name of a directory. If the destination is the name of a directory, then mv moves the file into that directory. Otherwise mv rename the file if possible.
2. Add comments to code.

Answer 1

root@PANKAJ:~/mydir# mv --version # Checking version of mv
mv (GNU coreutils) 8.25
Copyright (C) 2016 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by Mike Parker, David MacKenzie, and Jim Meyering.

root@PANKAJ:~/mydir# cat > testfile1 # Creating a file in name testfile1
Hello, this is testfile1.
^Z
[4]+ Stopped cat > testfile1

root@PANKAJ:~/mydir# cat > testfile2 # Creating a file in name testfile2
Hello, this is testfile2.
^Z
[5]+ Stopped cat > testfile2

root@PANKAJ:~/mydir# mkdir testdirectory # Creating a directory in name testdirectory

root@PANKAJ:~/mydir# mv testfile1 testdirectory # Move testfile1 to testdirectory

root@PANKAJ:~/mydir# # Below command Renames testfile2 to testfile3 as there is no such directory

root@PANKAJ:~/mydir# mv testfile2 testfile3

root@PANKAJ:~/mydir# #Let us now test if our command worked or not

root@PANKAJ:~/mydir# cat testfile2 # display content of testfile2
cat: testfile2: No such file or directory

root@PANKAJ:~/mydir# cat testfile3
Hello, this is testfile2.

root@PANKAJ:~/mydir# cat testfile1
cat: testfile1: No such file or directory

root@PANKAJ:~/mydir# cd testdirectory # Changing working directory to testdirectory

root@PANKAJ:~/mydir/testdirectory# cat testfile1
Hello, this is testfile1.

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On analyzing last 5 commands it is clear that mv command has moved the file to the target directory if the directory was found else it just renamed it.

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