function::local_clock_s - Linux

Overview

function::local_clock_s: Get a local clock in seconds.

Produces a monotonically increasing 64-bit integer, which corresponds to the number of seconds that have elapsed since the start of the epoch. Note that this is the number of wall seconds elapsed, not seconds as measured by a CPU clock cycle.

This function does not adjust for non-monotonic clock changes caused by leap seconds. It’s recommended that you use function::local_clock instead, if possible.

Syntax

function::local_clock_s(start_date_time)

Parameters

• start_date_time: The date and time from which to measure the elapsed time. If not specified, the start of the epoch (1970-01-01 00:00:00 UTC) is used.

Options/Flags

None.

Examples

Simple Use

function::local_clock_s()

Prints the number of seconds that have elapsed since the start of the epoch.

Measuring Elapsed Time

start_time=$(function::local_clock_s)
# Do something that takes time
end_time=$(function::local_clock_s)
elapsed_time=$((end_time - start_time))
echo "Elapsed time: $elapsed_time seconds"

Prints the number of seconds that have elapsed between the two function calls.

Common Issues

Non-Monotonic Clock Changes

This function does not adjust for non-monotonic clock changes caused by leap seconds. If this is a concern, use function::local_clock instead.

Integration

This command can be combined with other Linux commands or tools for advanced tasks. For example, it can be used to create a simple stopwatch:

while true; do
  clear
  current_time=$(function::local_clock_s)
  elapsed_time=$((current_time - start_time))
  echo "Elapsed time: $elapsed_time seconds"
  sleep 1
done

Related Commands

• function::local_clock: Get a local clock in nanoseconds.
• date: Print the current date and time.