How to get the file length in C on Linux given the address of the file (e.g. “/tmp/a.txt”)? This function returns the length of the file: #include <sys/stat.h> long file_length(char *f) { struct stat st; stat(f, &st); return st.st_size; }
How to Import a CMake project into Eclipse CDT? For example, the current CMake project source directory is ./src. mkdir ./cdt && cd ./cdt && cmake -G “Eclipse CDT4 – Unix Makefiles” ../src cmake will generate a Eclipse project in ./cdt and you can open it in Eclipse.
How to catch the kill signals sent by the kill command in C programs on Linux? For example, I have a daemon progd running, and will kill it by: pkill progd The question is how to catch the signal sent by the kill command and response to it in the progd program implemented in C…
Good tutorials on git branching. The “Git Branching” chapter of Pro Git book is the best one that I ever seen: http://git-scm.com/book/en/Git-Branching It deserve the time to study the whole chapter. If you are working with a git server, this chapter is especially useful: http://git-scm.com/book/en/Git-Branching-Remote-Branches
My webpage has one existing window.onload javascript function defined by a javascript plugin in the <head> section. Now, I defined a new one and add it to the end of the HTML page: <script type=”text/javascript”> window.onload = function () { // great work here } </script> I find the new one overwrites the old one…
Formatting code shortcuts in Eclipse. Shortcut: Ctrl + Shift + F No need to select the code.
How to make Emacs highlighting part of lines that go over 80 chars? I use the whitespace mode: ;; `lines-tail`, highlight the part that goes beyond the ;; limit of `whitespace-line-column` (require ‘whitespace) (setq whitespace-style ‘(face empty tabs lines-tail trailing)) (global-whitespace-mode t) More: https://github.com/zma/emacs-config/blob/master/.emacs Alternatively, you can run highlight-lines-matching-regexp with the expression .{81}. http://stackoverflow.com/questions/6344474/how-can-i-make-emacs-highlight-lines-that-go-over-80-chars
How to print a binary file in hexadecimal format of all content? Use xxd: xxd file.txt or xxd -p file.txt
How to change a wrong git commit message after I have pushed it to the server? If the remote repository is shared with others, it is better to let the wrong git commit message there. If you use the repository by your own and you are sure that no one else has pulled your latest…
How to convert between dos and unix file coding for files in Emacs? From Dos to Unix coding: M-x set-buffer-file-coding-system RET undecided-unix or C-x RET f undecided-unix Then save the file (C-x C-s). From Unix to Dos M-x set-buffer-file-coding-system RET undecided-dos or C-x RET f undecided-dos Then save the file (C-x C-s).
In Emacs, how to print the name of the current file that I am editing? The built-in function buffer-file-name gives the full path of your file. To get the file name: M-: buffer-file-name
How to get a tree-like view of the git commit history? My favorite command line: git log –graph –oneline It will prints a text based graph like (with colors): * b5dc8b9 Merge branch ‘master’ of https://github.com/layerzero/libi0 | | * 7514ef1 revised the README.md a little bit | * 6692428 align size to page for both…
What are all the bash supported comparison operators? The man 1 test contains all the operators supported in bash. An omitted EXPRESSION defaults to false. Otherwise, EXPRESSION is true or false and sets exit status. It is one of: ( EXPRESSION ) EXPRESSION is true ! EXPRESSION EXPRESSION is false EXPRESSION1 -a EXPRESSION2 both EXPRESSION1…
I am using Fedora 20. I installed the rpm from Oracle for the Oracle JDK. How to set up the environment so that the Java environment is Oracle JDK instead of the OpenJDK? The Oracle JDK is install to /usr/java/ directory. On my Fedora 20, it looks like this: $ ls /usr/java -l total 4…
How to rearrange Alt, Ctrl and Win keys on Linux: Win as Alt and Ctrl/Alt as Ctrl? On Linux, the Win key is seldom used. Mapping the Alt keys which are close to my thumb is damn convenient for Emacs users. Hence, the keyboard at the bottom line would look like: ———————————————————— |Ctrl|Alt|Ctrl| Space Bar…
How to detect memory leaks of C programs in Linux? I also have access to the source code of the program. There are many posts related to this: Easy and quick tools on Linux (while not very accurate): http://blog.thewebsitepeople.org/2011/03/linux-memory-leak-detection/ Valgrind: manual and a tutorial. gperftools has the Google Heap Profiler which can checks for memory…
How to change default OS for windows dual boot manager in Windows 7? The c:/boot/ in older Windows does not exist anymore. Open the Control Panel and click on the System icon. In the left pane, click on the Advanced system settings link. Under the Advanced tab, click on the Settings button under Startup and…
How to make Emacs run in command line by default? I do not want to open the X window. You have at least 2 choices. First choice: use emacs-nox and make it the default: # yum install emacs-nox # alternatives –config emacs and choose emacs-nox. Second choice: use emacs but with -nw to disable the…
How to debug/check network-related driver information on Linux? Several commands/tools that you may find usefull: Messages: dmesg grep NetworkManager /var/log/messages lshw: list hardware lshw -c network lsusb: list USB devices lsusb rfkill: enabling and disabling wireless devices rfkill unblock all rfkill event iwconfig: configure a wireless network interface iwconfig ifconfig: configure a network interface ifconfig
How to get the directory path and file name from a absolute path in C on Linux? For example, with “/foo/bar/baz.txt”, it will produce: “/foo/bar/” and “baz.txt”. You can use the APIs basename and dirname to parse the file name and directory name. A piece of C code: #include <libgen.h> #include <string.h> char* local_file =…