ChannelId must be an identifier for an open channel such as a Tcl standard channel (stdin, stdout, or stderr), the return value from an invocation of open or socket, or the result of a channel creation command provided by a Tcl extension.
set f [open somefile.txt] while {1} { set line [gets $f] if {[eof $f]} { close $f break } puts "Read line: $line" }
Read and print out the contents of a file by fixed-size records:
set f [open somefile.dat] fconfigure $f -translation binary set recordSize 40 while {1} { set record [read $f $recordSize] if {[eof $f]} { close $f break } puts "Read record: $record" }