Automatic variable
A Make variable such as $@, $< or $^ that refers to the current target or its prerequisites.
Scripting for EDA Automation — Technical Glossary
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C shell
csh and its extended version tcsh, an older Unix shell still used by many EDA site and tool setup scripts.
Dataclass
A Python class declared with @dataclass that stores fields and generates common methods automatically.
Environment module
A tool description loaded with module load that sets PATH and related variables for one tool version, in any shell.
Exit status
The number a process returns to its caller; 0 means success and any other value signals a specific failure.
Failure signature
An error message with run-specific values removed, used to group failures that share a cause.
File list
A text file of source paths, often with a .f extension, passed to a simulator or linter.
Hash
A Perl key-value table such as %count, read one value at a time with $count{key}.
Incremental build
Rebuilding only outputs whose inputs changed, based on file timestamps.
Liberty file
A .lib file that describes standard cells' function, timing and power for synthesis and timing tools.
Pattern rule
A Make rule using % to describe how to build a family of targets from matching prerequisites.
Phony target
A Make target that names an action rather than a file, declared with .PHONY so it always runs.
Random seed
The starting value for a pseudo-random generator; recording it makes a random test reproducible.
Regression
Repeated execution of a defined set of tests, often with several seeds, to detect behaviour that has broken.
Regular expression
A pattern language for matching text, used by grep, sed, awk, Python re and Tcl regexp.
SDC
Synopsys Design Constraints, a widely supported Tcl-based format for clocks, I/O delays and timing exceptions.
Shebang
The first line of a script, such as #!/usr/bin/env bash, that selects the interpreter.
Sigil
The symbol before a Perl name: $ for one value, @ for a list and % for a hash; it shows the kind of value being used.
Static timing analysis
Checking every timing path against constraints without simulation, as done by OpenSTA.
Strict mode
The Bash settings set -euo pipefail, which stop a script on failed commands, unset variables and failed pipeline stages.
Tcl dictionary
A Tcl value holding key-value pairs, managed with the dict command.
Tcl substitution
The single pass in which Tcl replaces $variables, [commands] and backslash escapes before running a command.
Timeout
A time limit after which a hung tool or simulation is stopped and reported.
Wait status
The raw value Perl stores in $? after system; the exit code is $? >> 8 and the low bits report a killing signal.
Waiver
A reviewed, narrowly matched exception that allows a known warning while any new warning still fails the check.
Worst negative slack
The most negative slack among all timing paths; a negative value means a constraint is violated.
argparse
The Python standard-library module that parses command-line options and generates help text.
getopts
A Bash built-in that parses short command-line options such as -t top -s seed.
pathlib
The Python standard-library module that represents file-system paths as objects.
setenv
The csh command that sets an environment variable, inherited by tools started from the shell; set creates a shell-only variable.