Open File On Linux Terminal

• Open File Ubuntu Terminal
• Open File On Linux Terminal Download

Arch Linux: pacman -Sy imagemagick Using ImageMagick to display a file. To display an image file, run display file name. For example: display logo.jpg. The command above creates a new window displaying the image named logo.jpg, as shown in the example below. Learn more about ImageMagick.

1. I'm going to show you two different ways to open a Linux terminal window. Option 1 Gnome desktop environment makes easy access of application, in order to access the terminal window, press the super key (aka Windows key) and you should see Terminal application listed on the left-hand side application pane if you don't see it listed on here.
2. The command xdg-open b2rR6eU9jJ.txt will open the text file in a text editor that is set to handle text files. The command will also work with other common file.

Prolog

This manual page is part of the POSIX Programmer's Manual. The Linux implementation of thisinterface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

Name

open - open a file

Synopsis

#include
#include

int open(const char *path, intoflag, .. );

Description

The open() function shall establish the connection between a file and a file descriptor. It shall create an open file description that refers to afile and a file descriptor that refers to that open file description. The file descriptor is used by other I/O functions to refer to that file. The pathargument points to a pathname naming the file.

The open() function shall return a file descriptor for the named file that is the lowest file descriptor not currently open for that process. Theopen file description is new, and therefore the file descriptor shall not share it with any other process in the system. The FD_CLOEXEC file descriptor flagassociated with the new file descriptor shall be cleared.

The file offset used to mark the current position within the file shall be set to the beginning of the file.

The file status flags and file access modes of the open file description shall be set according to the value of oflag.

Values for oflag are constructed by a bitwise-inclusive OR of flags from the following list, defined in . Applications shallspecify exactly one of the first three values (file access modes) below in the value of oflag:

O_APPEND

If set, the file offset shall be set to the end of the file prior to each write.

O_CREAT

If the file exists, this flag has no effect except as noted under O_EXCL below. Otherwise, the file shall be created; the user ID of the file shall be setto the effective user ID of the process; the group ID of the file shall be set to the group ID of the file's parent directory or to the effective group ID ofthe process; and the access permission bits (see ) of the file mode shall be set to the value of the third argument taken as typemode_t modified as follows: a bitwise AND is performed on the file-mode bits and the corresponding bits in the complement of the process' file modecreation mask. Thus, all bits in the file mode whose corresponding bit in the file mode creation mask is set are cleared. When bits other than the filepermission bits are set, the effect is unspecified. The third argument does not affect whether the file is open for reading, writing, or for both.Implementations shall provide a way to initialize the file's group ID to the group ID of the parent directory. Implementations may, but need not, provide animplementation-defined way to initialize the file's group ID to the effective group ID of the calling process.

O_DSYNC

Write I/O operations on the file descriptor shall complete as defined by synchronized I/O data integrity completion.

O_EXCL

If O_CREAT and O_EXCL are set, open() shall fail if the file exists. The check for the existence of the file and the creation of the file if it doesnot exist shall be atomic with respect to other threads executing open() naming the same filename in the same directory with O_EXCL and O_CREAT set. IfO_EXCL and O_CREAT are set, and path names a symbolic link, open() shall fail and set errno to [EEXIST], regardless of the contents of thesymbolic link. If O_EXCL is set and O_CREAT is not set, the result is undefined.

O_NOCTTY

If set and path identifies a terminal device, open() shall not cause the terminal device to become the controlling terminal for the process.

O_NONBLOCK

When opening a FIFO with O_RDONLY or O_WRONLY set:

*

If O_NONBLOCK is set, an open() for reading-only shall return without delay. An open() for writing-only shall return an error if no processcurrently has the file open for reading.

*

If O_NONBLOCK is clear, an open() for reading-only shall block the calling thread until a thread opens the file for writing. An open() forwriting-only shall block the calling thread until a thread opens the file for reading.

When opening a block special or character special file that supports non-blocking opens:

O_RSYNC

Read I/O operations on the file descriptor shall complete at the same level of integrity as specified by the O_DSYNC and O_SYNC flags. If both O_DSYNC andO_RSYNC are set in oflag, all I/O operations on the file descriptor shall complete as defined by synchronized I/O data integrity completion. If bothO_SYNC and O_RSYNC are set in flags, all I/O operations on the file descriptor shall complete as defined by synchronized I/O file integrity completion.

O_SYNC

Write I/O operations on the file descriptor shall complete as defined by synchronized I/O file integrity completion.

O_TRUNC

If the file exists and is a regular file, and the file is successfully opened O_RDWR or O_WRONLY, its length shall be truncated to 0, and the mode andowner shall be unchanged. It shall have no effect on FIFO special files or terminal device files. Its effect on other file types is implementation-defined. Theresult of using O_TRUNC with O_RDONLY is undefined.

If O_CREAT is set and the file did not previously exist, upon successful completion, open() shall mark for update the st_atime,st_ctime, and st_mtime fields of the file and the st_ctime and st_mtime fields of the parent directory.

If O_TRUNC is set and the file did previously exist, upon successful completion, open() shall mark for update the st_ctime and st_mtimefields of the file.

If both the O_SYNC and O_DSYNC flags are set, the effect is as if only the O_SYNC flag was set.

If path refers to a STREAMS file, oflag may be constructed from O_NONBLOCK OR'ed with either O_RDONLY, O_WRONLY, or O_RDWR. Other flag valuesare not applicable to STREAMS devices and shall have no effect on them. The value O_NONBLOCK affects the operation of STREAMS drivers and certain functionsapplied to file descriptors associated with STREAMS files. For STREAMS drivers, the implementation of O_NONBLOCK is device-specific.

If path names the master side of a pseudo-terminal device, then it is unspecified whether open() locks the slave side so that it cannot beopened. Conforming applications shall call unlockpt() before opening the slave side.

The largest value that can be represented correctly in an object of type off_t shall be established as the offset maximum in the open filedescription.

Return Value

Upon successful completion, the function shall open the file and return a non-negative integer representing the lowest numbered unused file descriptor.Otherwise, -1 shall be returned and errno set to indicate the error. No files shall be created or modified if the function returns -1.

Errors

The open() function shall fail if:

EAGAIN

The path argument names the slave side of a pseudo-terminal device that is locked.

EINVAL

The value of the oflag argument is not valid.

ELOOP

More than {SYMLOOP_MAX} symbolic links were encountered during resolution of the path argument.

ENAMETOOLONG

As a result of encountering a symbolic link in resolution of the path argument, the length of the substituted pathname string exceeded {PATH_MAX}.

ENOMEM

The path argument names a STREAMS file and the system is unable to allocate resources.

ETXTBSY

The file is a pure procedure (shared text) file that is being executed and oflag is O_WRONLY or O_RDWR.

The following sections are informative.

Examples

Opening a File for Writing by the Owner

The following example opens the file /tmp/file, either by creating it (if it does not already exist), or by truncating its length to 0 (if it doesexist). In the former case, if the call creates a new file, the access permission bits in the file mode of the file are set to permit reading and writing bythe owner, and to permit reading only by group members and others.

If the call to open() is successful, the file is opened for writing.

Opening a File Using an Existence Check

The following example uses the open() function to try to create the LOCKFILE file and open it for writing. Since the open() functionspecifies the O_EXCL flag, the call fails if the file already exists. In that case, the program assumes that someone else is updating the password file andexits.

Open File Ubuntu Terminal

Opening a File for Writing

The following example opens a file for writing, creating the file if it does not already exist. If the file does exist, the system truncates the file tozero bytes.

Application Usage

None.

Rationale

Convert excel 4 0 macro to vba. Except as specified in this volume of IEEE Std 1003.1-2001, the flags allowed in oflag are not mutually-exclusive and any number of them may be usedsimultaneously.

Some implementations permit opening FIFOs with O_RDWR. Since FIFOs could be implemented in other ways, and since two file descriptors can be used to thesame effect, this possibility is left as undefined.

Open File On Linux Terminal Download

See getgroups() about the group of a newly created file.

The use of open() to create a regular file is preferable to the use of creat(), because the latter is redundant and included only forhistorical reasons.

The use of the O_TRUNC flag on FIFOs and directories (pipes cannot be open()-ed) must be permissible without unexpected side effects (for example,creat() on a FIFO must not remove data). Since terminal special files might have type-ahead data stored in the buffer, O_TRUNC should not affect theircontent, particularly if a program that normally opens a regular file should open the current controlling terminal instead. Other file types, particularlyimplementation-defined ones, are left implementation-defined.

IEEE Std 1003.1-2001 permits [EACCES] to be returned for conditions other than those explicitly listed.

The O_NOCTTY flag was added to allow applications to avoid unintentionally acquiring a controlling terminal as a side effect of opening a terminal file.This volume of IEEE Std 1003.1-2001 does not specify how a controlling terminal is acquired, but it allows an implementation to provide this on open()if the O_NOCTTY flag is not set and other conditions specified in the Base Definitions volume of IEEE Std 1003.1-2001, Chapter 11, General Terminal Interfaceare met. The O_NOCTTY flag is an effective no-op if the file being opened is not a terminal device.

In historical implementations the value of O_RDONLY is zero. Because of that, it is not possible to detect the presence of O_RDONLY and another option.Future implementations should encode O_RDONLY and O_WRONLY as bit flags so that:

In general, the open() function follows the symbolic link if path names a symbolic link. However, the open() function, when called withO_CREAT and O_EXCL, is required to fail with [EEXIST] if path names an existing symbolic link, even if the symbolic link refers to a nonexistent file.This behavior is required so that privileged applications can create a new file in a known location without the possibility that a symbolic link might causethe file to be created in a different location.

For example, a privileged application that must create a file with a predictable name in a user-writable directory, such as the user's home directory, couldbe compromised if the user creates a symbolic link with that name that refers to a nonexistent file in a system directory. If the user can influence thecontents of a file, the user could compromise the system by creating a new system configuration or spool file that would then be interpreted by the system. Thetest for a symbolic link which refers to a nonexisting file must be atomic with the creation of a new file.

The POSIX.1-1990 standard required that the group ID of a newly created file be set to the group ID of its parent directory or to the effective group ID ofthe creating process. FIPS 151-2 required that implementations provide a way to have the group ID be set to the group ID of the containing directory, but didnot prohibit implementations also supporting a way to set the group ID to the effective group ID of the creating process. Conforming applications should notassume which group ID will be used. If it matters, an application can use chown() to set the group ID after the file is created, or determine under whatconditions the implementation will set the desired group ID.

Future Directions

None.

See Also

chmod(), close(), creat(), dup(), fcntl(), lseek(), read(), umask(), unlockpt(),write(), the Base Definitions volume of IEEE Std 1003.1-2001, , , Good digital art programs for beginners.

Copyright

Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1,2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright ©2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and theoriginal IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained onlineat http://www.opengroup.org/unix/online.html .

Referenced By

shortrpm(1)