File input and output commands

These commands include those to search ASCII-sorted data files, copy files, duplicate file descriptors, control file access options, retrieve open file status, and create pipes with the pipe system call. An interface to the select system call is available on UNIX systems that support it.

Tcl file I/O is implemented on top of the stdio library. By default, the file is buffered. When communicating to a process through a pipe, a flush command should be issued to force the data out. Alternatively, the fcntl command may be used to set the buffering mode of a file to line-buffered or unbuffered.

Available commands are:

bsearch(TCL)

searchs an open file for a match

close(TCL)

closes an open file

copyfile(TCL)

copies the remainder of file1 to file2

dup(TCL)

duplicates an open file

eof(TCL)

checks for an end-of-file condition on an open file

fcntl(TCL)

sets, clears, or returns file options

file(TCL)

manipulates file names and attributes

flock(TCL)

creates a lock on all or part of a file

flush(TCL)

flushes buffered output for a file

for_file(TCL)

implements a loop over contents of a file

funlock(TCL)

removes a lock created by flock(TCL)

frename(TCL)

renames an old path to a new path

fstat(TCL)

obtains status information on an open file

gets(TCL)

reads a line from a file

lgets(TCL)

reads the next Tcl list from a file and discards the terminating newline

open(TCL)

opens a file

pipe(TCL)

creates a pipe

puts(TCL)

writes to a file

read(TCL)

reads from a file

read_file(TCL)

reads a file and returns its contents as a string

select(TCL)

waits for files to come available or satisfy conditions

seek(TCL)

changes the access position for an open file

tell(TCL)

returns the current access position for an open file

write_file(TCL)

writes strings to a specified file