nits - Developer IT

UNIX Question to b answered??? [closed]

- by Nits

Create a tree structure named ‘training’ in which there are 3 subdirectories – ‘level 1’,’ level2’ and ‘cep’. Each one is again further divided into 3. The ‘level 1’ is divided into ‘sdp’, ‘re’ and ‘se’. From the subdirectory ‘se’ how can one reach the home directory in one step and also how to navigate to the subdirectory ‘sdp’ in one step? Give the commands, which do the above actions? How will you copy a directory structure dir1 to dir2 ? (with all the subdirectories) How can you find out if you have the permission to send a message? Find the space occupied ( in Bytes) by the /home directory including all its subdirectories. What is the command for printing the current time in 24-hour format? What is the command for printing the year, month, and date with a horizontal tab between the fields? Create the following files: chapa, chapb, chapc, chapd, chape, chapA, chapB, chapC, chapD, chapE, chap01, chap02, chap03, chap04, chap05, chap11, chap12, chap13, chap14, and chap15. With reference to question 7, What is the command for listing all files ending in small letters? With reference to question 7, What is the command for listing all files ending in capitals? With reference to question 7, What is the command for listing all files whose last but one character is 0? With reference to question 7, What is the command for listing all files which end in small letters but not ‘a’ and ‘c’? In an organisation one wants to know how many programmers are there. The employee data is stored in a file called ‘personnel’ with one record per employee. Every record has field for designation. How can grep be used for this purpose? In the organisation mentioned in question 12 how can sed be used to print only the records of all employees who are programmers. In the organisation mentioned in question 12 how can sed be used to change the designation ‘programmer’ to ‘software professional’ every where in the ‘personnel’ file Find out about the sleep command and start five jobs in the background, each one sleeping for 10 minutes. How do you get the status of all the processes running on the system? i.e. using what option?

Read the article

Optimizing hash lookup & memory performance in Go

- by Moishe

As an exercise, I'm implementing HashLife in Go. In brief, HashLife works by memoizing nodes in a quadtree so that once a given node's value in the future has been calculated, it can just be looked up instead of being re-calculated. So eg. if you have a node at the 8x8 level, you remember it by its four children (each at the 2x2 level). So next time you see an 8x8 node, when you calculate the next generation, you first check if you've already seen a node with those same four children. This is extended up through all levels of the quadtree, which gives you some pretty amazing optimizations if eg. you're 10 levels above the leaves. Unsurprisingly, it looks like the perfmance crux of this is the lookup of nodes by child-node values. Currently I have a hashmap of {&upper_left_node,&upper_right_node,&lower_left_node,&lower_right_node} -> node So my lookup function is this: func FindNode(ul, ur, ll, lr *Node) *Node { var node *Node var ok bool nc := NodeChildren{ul, ur, ll, lr} node, ok = NodeMap[nc] if ok { return node } node = &Node{ul, ur, ll, lr, 0, ul.Level + 1, nil} NodeMap[nc] = node return node } What I'm trying to figure out is if the "nc := NodeChildren..." line causes a memory allocation each time the function is called. If it does, can I/should I move the declaration to the global scope and just modify the values each time this function is called? Or is there a more efficient way to do this? Any advice/feedback would be welcome. (even coding style nits; this is literally the first thing I've written in Go so I'd love any feedback)

Read the article

How to pre-process CSV data for FasterCSV?

- by Katherine Chalmers

We're having a significant number of problems creating a bulk upload function for our little app. We're using the FasterCSV gem to upload data to a MySQL database but he Faster CSV is so twitchy and precise in its requirements that it constantly breaks with malformed CSV errors and time out errors. The csv files are generally created by users' pasting text from their web sites or from Microsoft Word docs so it is not reasonable to expect that there will never be odd characters like smart quotes or accents in the data. Also users aren't going to be readily able to identify whether their data is perfect enough for FasterCSV or not. We need to find a way to fix it for them automatically. Is there a good way or a reliable tool for pre-processing CSV data to fix any nits in the data before having the FasterCSV gem process it?

Read the article

Javascript - undefined cookie value?

- by Computeras

Try running the code, I know the problem is in the 1. part. Thanks in advance, P.S. I'm a newbie in JS. <html> <head> <script> { //1. part var Cookies = ""; function createCookie(name,value,days) { if (days) { var date = new Date(); date.setTime(date.getTime()+(days*24*60*60*1000)); var expires = "; expires="+date.toGMTString(); } else var expires = ""; document.cookie = name+"="+value+expires+"; path=/"; } function readCookie(name) { var nameEQ = name + "="; var ca = document.cookie.split(';'); for(var i=0;i < ca.length;i++) { var c = ca[i]; while (c.charAt(0)==' ') c = c.substring(1,c.length); if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length); } return null; } function eraseCookie(name) { createCookie(name,"",-1); } //2. part function saveIt(name) { var x = document.forms['cookieform'].cookievalue.value; if (!x) alert('Please fill in a value in the input box.'); else { Cookies.create(name,x,7); alert('Cookie created'); } } function readIt(name) { alert('The value of the cookie is ' + Cookies[name]); } function eraseIt(name) { Cookies.erase(name); alert('Cookie erased'); } function init() { for (var i=1;i<3;i++) { var x = Cookies['ppkcookie' + i]; if (x) alert('Cookie ppkcookie' + i + '\nthat you set on a previous visit, is still active.\nIts value is ' + x); } } } </script> <body> <form name = "forma"> <input type = "text" name = "cookievalue"> <input type = "button" value = "Spremi" onClick = "saveIt('ppkcookie1')"> <input type = "button" value = "Ispisi" onClick = "readIt('ppkcookie1')"> </form> </body> </html>

Developer IT