There are basically three modes of handling files. Read, Write and Append.
Below are the ways:
#1. r -> Read a file, file must exist.
#2. w -> Write a file, If file exists, then file will get truncated.
#3. a -> Append the file, file must exist.
#4. r+ -> Open a file for read and write both, File must exist.
#5. w+-> Open a file for read and write both, If file exists, then it will truncate the file with zero length or if file doesn’t exist then it creates one.
#6. a+ -> Open a file for reading and writing both, if file doesn’t exist, then it creates one. If reading then it start from beginning and writing starts with appending.
Reading a file
Syntax: [open <file_name> r]
set file_name file1.tcl
set read_file_name [open $file_name r]
set file_details [read $read_file_name]
puts $file_details
close $file_name
Writing a file
Syntax: [open <file_name> w]
set file_name file1.tcl
set write_file_name [open $file_name w]
puts $write_file_name “This will be written in file1”
close $write_file_name
Once we are done with writing or reading a file, we need to close the file.
Written by
Swasti Pujari
Associate Director, Backend Engineering at CoreIC Technologies, with 15+ years in VLSI Physical Design and backend engineering. Previously Practice Head at UST Global, leading Physical Design, STA, EMIR, DFT, and Physical Verification. Delivered 3nm, 6nm and 7nm projects for AMD, Intel, and Microchip, and published IEEE research on hybrid AI-EDA floorplanning.
