Click here to close now.



Welcome!

Linux Containers Authors: Elizabeth White, Pat Romanski, Liz McMillan, David Sprott, Plutora Blog

Related Topics: Linux Containers, Open Source Cloud

Linux Containers: Blog Feed Post

Things You May or May Not Know About Linux “find” Command

How to utilize find in a less common but very useful way

In the first part of our series we described how to use find (and locate) to search for files using their names. Today we are going to review how to utilize find in a less common but very useful way. But first a few words on testing (okay, this might not be necessary for everyone, but bear with me!).

1. How to test
It is very important to remember that the find command allows you to create a list of objects having the value of a property the same, greater or smaller then given “n” — which stands for a number of days defined as 24 hours periods, with any frictional part ignored:

  • +n – value of file property grater than n,
  • n – value of file property the same as n,
  • -n – value of file property smaller than n.

2. Search using time related information.
One of the most useful features of find is the ability to separate files based on the time of their creation, access and modification. This is done by the family of “time” tests. In “n” language, 47 hours will be given the same value as 25 hours (n=1). This behaviour can be changed by adding the option “-daystart” (measure time from beginning of today, so “n” for yesterday equals 1 in front of a test. Have a look at these time definitions below:

  • -mtime n (Modification TIME) – probably the most useful from time-related tests, allowing to search files based on their modification time. If you want to have a list of all log files modified 2 days ago (or to be precise between 48 and 72 hours ago) you can run:
    find /var/log -mtime 2
  • -atime n (Access TIME) – the results based on a file’s last access time. If you want to see all logs accessed today you can run:
    find /var/log -atime 0

    Please remember it might be misleading if you check the file system mounted with option -noatime (which improves performance).

  • -ctime n ([status] Change TIME) – this test searches files based on change of status (It means ownership, access privileges or type). For example you want to find which (or any at all) of the files in your home directory have changed status in the last 48 hours (which might indicate problems) you can run:
    find ~ -ctime -1

Measuring time in days is not always very handy. Sometimes it is necessary to find more recent changes. To make it possible, the above test has minuets-base equivalents:

  • -mmin n – test modification time but in minutes rather than days;
  • -amin n – test access time but in minutes rather than days;
  • -cmin n – test status change time but in minutes rather than days.

Imagine the following situation: You have downloaded a file under five minutes ago, but you are not sure where you have saved it. You can try the following command:

find ~ -mmin -5

In this scenario mmin can be change to amin or cmin, because all “three times” have the same initial value.

Lastly, there are tests allow you to search files in relation to a property of another file. For example:

  • -newer file – returns files modified more recently than the given file,
  • -anewer file – return files accessed more recently than the given file,
  • -cnewer file – return files with the status changed more recently than for the given file.

For example, the following command will list all files accessed later than file DSCF1002.avi in directory /home/movies:

find /home/movies -anewer DSCF1002.avi

There is also a fourth ‘newer’ test:

  • -newerXY reference – which compares timestamp with the given timestamp of the reference file. XY has to be substituted by one or two from the following timestamp type:
    • a – access time,
    • B – birth (creation) time,
    • c – inode status change time,
    • m – modification time,
    • t – reference is interpreted directly as a time.

Please remember that not all combinations are supported (notable X cannot equal t) and B is not supported on all systems. For example, to get the list of all files accessed in /var/cache later than (in BST) July 20th 10:45:32  2011:

find /var/cache -newerat ‘Jul 20 10:45:32 BST 2011’

To create another list with files modified later than the last access to your .profile file:

find /var/cache -newerma ~/.profile

There is one more test that allows you to search based on a time-related parameter:

  • -used n – creates the list of files accessed “n” days after its status was last changed. To find not very often accessed files (let say one month) in /var directory, use this command:
    find /var/ -used +30

Appendix. ls and time
You can try to create similar lists with a little help from the ls command. There are three ls commands that correspond to the above find test. They allow you to sort files according to:

  • -t – modification time (mtime);
  • -u – access time (atime);
  • -c – status change time (ctime).

Option -t simply sorts by modification time, but option -u and -c behave different in connection with other options:

  • ls -u – sorts by access time (receptively ls -c sorts by status change time);
  • ls -ul – shows access time but sorts by name (ls -cl – shows status change time but sorts by name);
  • ls -ult – shows and sorts by access time (ls -clt – shows and sorts by status change time).

Read the original blog entry...

More Stories By Hovhannes Avoyan

Hovhannes Avoyan is the CEO of PicsArt, Inc.,

@ThingsExpo Stories
Fortunately, meaningful and tangible business cases for IoT are plentiful in a broad array of industries and vertical markets. These range from simple warranty cost reduction for capital intensive assets, to minimizing downtime for vital business tools, to creating feedback loops improving product design, to improving and enhancing enterprise customer experiences. All of these business cases, which will be briefly explored in this session, hinge on cost effectively extracting relevant data from ...
As enterprises work to take advantage of Big Data technologies, they frequently become distracted by product-level decisions. In most new Big Data builds this approach is completely counter-productive: it presupposes tools that may not be a fit for development teams, forces IT to take on the burden of evaluating and maintaining unfamiliar technology, and represents a major up-front expense. In his session at @BigDataExpo at @ThingsExpo, Andrew Warfield, CTO and Co-Founder of Coho Data, will dis...
Companies can harness IoT and predictive analytics to sustain business continuity; predict and manage site performance during emergencies; minimize expensive reactive maintenance; and forecast equipment and maintenance budgets and expenditures. Providing cost-effective, uninterrupted service is challenging, particularly for organizations with geographically dispersed operations.
The Quantified Economy represents the total global addressable market (TAM) for IoT that, according to a recent IDC report, will grow to an unprecedented $1.3 trillion by 2019. With this the third wave of the Internet-global proliferation of connected devices, appliances and sensors is poised to take off in 2016. In his session at @ThingsExpo, David McLauchlan, CEO and co-founder of Buddy Platform, will discuss how the ability to access and analyze the massive volume of streaming data from mil...
WebSocket is effectively a persistent and fat pipe that is compatible with a standard web infrastructure; a "TCP for the Web." If you think of WebSocket in this light, there are other more hugely interesting applications of WebSocket than just simply sending data to a browser. In his session at 18th Cloud Expo, Frank Greco, Director of Technology for Kaazing Corporation, will compare other modern web connectivity methods such as HTTP/2, HTTP Streaming, Server-Sent Events and new W3C event APIs ...
Join us at Cloud Expo | @ThingsExpo 2016 – June 7-9 at the Javits Center in New York City and November 1-3 at the Santa Clara Convention Center in Santa Clara, CA – and deliver your unique message in a way that is striking and unforgettable by taking advantage of SYS-CON's unmatched high-impact, result-driven event / media packages.
SYS-CON Events announced today that FalconStor Software® Inc., a 15-year innovator of software-defined storage solutions, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. FalconStor Software®, Inc. (NASDAQ: FALC) is a leading software-defined storage company offering a converged, hardware-agnostic, software-defined storage and data services platform. Its flagship solution FreeStor®, utilizes a horizonta...
Silver Spring Networks, Inc. (NYSE: SSNI) extended its Internet of Things technology platform with performance enhancements to Gen5 – its fifth generation critical infrastructure networking platform. Already delivering nearly 23 million devices on five continents as one of the leading networking providers in the market, Silver Spring announced it is doubling the maximum speed of its Gen5 network to up to 2.4 Mbps, increasing computational performance by 10x, supporting simultaneous mesh communic...
The cloud promises new levels of agility and cost-savings for Big Data, data warehousing and analytics. But it’s challenging to understand all the options – from IaaS and PaaS to newer services like HaaS (Hadoop as a Service) and BDaaS (Big Data as a Service). In her session at @BigDataExpo at @ThingsExpo, Hannah Smalltree, a director at Cazena, will provide an educational overview of emerging “as-a-service” options for Big Data in the cloud. This is critical background for IT and data profes...
Eighty percent of a data scientist’s time is spent gathering and cleaning up data, and 80% of all data is unstructured and almost never analyzed. Cognitive computing, in combination with Big Data, is changing the equation by creating data reservoirs and using natural language processing to enable analysis of unstructured data sources. This is impacting every aspect of the analytics profession from how data is mined (and by whom) to how it is delivered. This is not some futuristic vision: it's ha...
With the Apple Watch making its way onto wrists all over the world, it’s only a matter of time before it becomes a staple in the workplace. In fact, Forrester reported that 68 percent of technology and business decision-makers characterize wearables as a top priority for 2015. Recognizing their business value early on, FinancialForce.com was the first to bring ERP to wearables, helping streamline communication across front and back office functions. In his session at @ThingsExpo, Kevin Roberts...
Cognitive Computing is becoming the foundation for a new generation of solutions that have the potential to transform business. Unlike traditional approaches to building solutions, a cognitive computing approach allows the data to help determine the way applications are designed. This contrasts with conventional software development that begins with defining logic based on the current way a business operates. In her session at 18th Cloud Expo, Judith S. Hurwitz, President and CEO of Hurwitz & ...
One of the bewildering things about DevOps is integrating the massive toolchain including the dozens of new tools that seem to crop up every year. Part of DevOps is Continuous Delivery and having a complex toolchain can add additional integration and setup to your developer environment. In his session at @DevOpsSummit at 18th Cloud Expo, Miko Matsumura, Chief Marketing Officer of Gradle Inc., will discuss which tools to use in a developer stack, how to provision the toolchain to minimize onboa...
With an estimated 50 billion devices connected to the Internet by 2020, several industries will begin to expand their capabilities for retaining end point data at the edge to better utilize the range of data types and sheer volume of M2M data generated by the Internet of Things. In his session at @ThingsExpo, Don DeLoach, CEO and President of Infobright, will discuss the infrastructures businesses will need to implement to handle this explosion of data by providing specific use cases for filte...
SYS-CON Events announced today that Pythian, a global IT services company specializing in helping companies adopt disruptive technologies to optimize revenue-generating systems, has been named “Bronze Sponsor” of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2015 at the Javits Center in New York, New York. Founded in 1997, Pythian is a global IT services company that helps companies compete by adopting disruptive technologies such as cloud, Big Data, advanced analytics, and DevO...
SYS-CON Events announced today that Avere Systems, a leading provider of enterprise storage for the hybrid cloud, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Avere delivers a more modern architectural approach to storage that doesn’t require the overprovisioning of storage capacity to achieve performance, overspending on expensive storage media for inactive data or the overbuilding of data centers ...
SYS-CON Events announced today that Commvault, a global leader in enterprise data protection and information management, has been named “Bronze Sponsor” of SYS-CON's 18th International Cloud Expo, which will take place on June 7–9, 2016, at the Javits Center in New York City, NY, and the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Commvault is a leading provider of data protection and information management...
SYS-CON Events announced today that Alert Logic, Inc., the leading provider of Security-as-a-Service solutions for the cloud, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Alert Logic, Inc., provides Security-as-a-Service for on-premises, cloud, and hybrid infrastructures, delivering deep security insight and continuous protection for customers at a lower cost than traditional security solutions. Ful...
SYS-CON Events announced today that Interoute, owner-operator of one of Europe's largest networks and a global cloud services platform, has been named “Bronze Sponsor” of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2015 at the Javits Center in New York, New York. Interoute is the owner-operator of one of Europe's largest networks and a global cloud services platform which encompasses 12 data centers, 14 virtual data centers and 31 colocation centers, with connections to 195 ad...
SYS-CON Events announced today that Men & Mice, the leading global provider of DNS, DHCP and IP address management overlay solutions, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. The Men & Mice Suite overlay solution is already known for its powerful application in heterogeneous operating environments, enabling enterprises to scale without fuss. Building on a solid range of diverse platform support,...