* File pointer to hold reference to our file */ * C program to create a file and write data into file. Program to create a file and write data into file /** Alternatively, you can view file contents by opening the newly created file in your favourite text editor. Hence there will be no output on console. I have restricted context of this post to create a file and store data into file.
On success it return pointer to FILE type otherwise NULL pointer. We will use w file mode to create a file.įopen("file-name", "read-mode") function accepts two parameter first file name to read/create/write/append data, next is file open mode. You can open a file in basic three different mode r(read), w(write) and a(append) mode. fopen() function is used to open a file in different mode. Create or open file using fopen() function.Declare a FILE type pointer variable to store reference of file, say FILE * fPtr = NULL.Step by step descriptive logic to create a file and write data into file.
HOW TO MAKE A NEW FILE ON LINUX C FILE HOW TO
In this post I will only explain how to create a file and write data into file. The pointer to FILE type will hold a logical reference to our physically existed file on disk (hard disk). To perform any operation on file we use a built-in FILE structure. Learn how to create a file and write contents to it in C programming.īasic input and output, Pointers, Structures, File handling How to create a file in C?Ĭ programming provides built-in support to create, read, write and append data to file.
How to create a file in C programming? C program to input a string from user and store it in a text file. We can make it shorter with this: $ python -c 'import sys,os f=sys.argv '$'\n''with open(f,"a"): os.utime(f,None)' mysecondfile.txtĪnd in Perl: $ perl -e 'open(my $fh,">","/tmp/perlfile")'ġ Other types of files such as hard/soft links,character or block special devices, directory,named pipes, or sockets require entirely different syscalls.Write a C program to create a file and write contents in it. Python one-liner: $ python -c 'import sys,os f=sys.argv os.utime(f,None) if os.path.exists(f) else open(f,"a").close' myfile.txt Of course, at the level of programming or scripting we may want to create a file as well, especially for efficiency purposes (because calling external commands such as touch from a Perl script or Python will require additional resources). But they perform the necessary syscall and that allows us to adapt the commands. Of course, all the above mentioned utilities do not exclusively create files. mktemp or tempfile ( for creating temporary files that do not need to exist between reboots !).truncate -size 0 /tmp/new_filename.txt.As mentioned, anything that can perform open(), openat() and, create() syscalls will create a file. In most shells nowadays true or : is a built-in, so doing : > /tmp/new_file is going to be more efficient, although marginally compared to touch /tmp/new_file.īut of course it does not stop there. That means, if the filename does not exist - it will be created, and if it does - the data will be truncated (and therefore gone, so > should be used with care). The > operator specifically calls the openat() system call with O_WRONLY|O_CREAT|O_TRUNC flags. Note also that a filename - is treated specially, so if you do want to create a file that is named literally -, you'll have to enclose that into single or double quotes.īy contrast, > is a shell redirection operator for stdout stream.
HOW TO MAKE A NEW FILE ON LINUX C FILE UPDATE
Its original purpose is to update the access and modification time of a file, however if the file does not exist - it will be created. Most commonly new filename is created with something like this: That means if you call any command-line utility that does these system calls, you can create a new empty file. In general, creating any regular 1 file on Linux involves open(2), openat(2), and creat(2) system calls (and specifically with O_CREAT flags).