Convert string to integer bash how to#
Convert string to integer bash manual#
Convert string to integer bash code#

(UTC), Thursday, 1 January 1970, not counting leap seconds. That have elapsed since 00:00:00 Coordinated Universal Time 5 Answers Sorted by: 92 The standard solution: expr d1 - d2 You can also do: echo ( ( d1 - d2 )) but beware that this will treat 07 as an octal number (so 07 is the same as 7, but 010 is different than 10 ). Unix time (also known as POSIX time or Epoch time) is a systemįor describing instants in time, defined as the number of seconds

Convert string to integer bash how to#

These examples are showing how to parse date in human readable form to unix timestamp in either milliseconds or seconds. String date = dateFormat.format(currentDate) ĭate +'%Y-%m-%d %H:%M:%S' -d Date to Timestamp Examples SimpleDateFormat dateFormat = new SimpleDateFormat('YYYY-MM-dd HH:mm:ss') These examples are showing how to convert timestamp - either in milliseconds or seconds to human readable form. These examples are showing how to get current date and time that could be presented to the end-user. Long ts = System.currentTimeMillis()/1000 These examples are returning timestamp in seconds, although some of the languages are returning timestamp in milliseconds. These examples are showing how to get current unix timestamp in seconds. Or you can construct URL with your timestamp. If you want to convert timestamp, it is sufficient to either enter your timestamp into input area, No slides, no clickers-just me and the audience typing away at the command line, exploring the wondrous world of Bash.Timestamp Online is timestamp converver between unix timestamp and human readable form date. This article is based on a talk I gave at OSCON, where I presented the live-coding workshop You Don't Know Bash. Since there's no getting around the command line in this example, using Bash directly is preferable. P = subprocess.Popen(cmd, stdout=subprocess.PIPE, shell=True) # Use the subprocess module to fetch the return output

Convert string to integer bash code#

And although we could utilize code contortions such as echo 'Found 42 '$type's', the best way to solve this problem is to use curly braces: echo 'Found 42 $'.format(t) We can't simply add an s to $type since that would turn it into a different variable, $types. Say the variable $type is given to us as a singular noun and we want to add an s at the end of our sentence.

Consider the following scenario: type='article' To understand why that is, let's take a step back and revisit how we usually output variables in Bash. You'll notice that simply doing echo $allThreads will output only the first element. Now that we've initialized the array, let's retrieve a few of its elements. Otherwise, Bash will treat the variable name as a program to execute, and the = as its first parameter! And just as with any other Bash variable, make sure to leave no spaces around the equal sign.

In this example, all the elements are numbers, but it need not be the case-arrays in Bash can contain both numbers and strings, e.g., myArray=(1 2 'three' 4 'five') is a valid expression. The first thing we'll do is define an array containing the values of the -threads parameter that we want to test: allThreads=(1 2 4 8 16 32 64 128) For the sake of simplicity, we'll treat the pipeline as a compiled C++ black box where the only parameter we can tweak is the number of threads reserved for data processing. As a first step, you want to do a parameter sweep to evaluate how well the pipeline makes use of threads. To that end, let's consider a real-world scenario and how Bash can help: You are leading a new effort at your company to evaluate and optimize the runtime of your internal data pipeline. Rest assured, however, the intent of this article is to avoid having you RTFM.

Convert string to integer bash manual#

Writing about Bash is challenging because it's remarkably easy for an article to devolve into a manual that focuses on syntax oddities.

eBook: An introduction to programming with Bash.

Try for free: Red Hat Learning Subscription.