How to escape the XML CData section ending sequence ]]>? The ]]> sequence itself may be part of the content in a CData section. One solution is to split the ]]> token into 2 CData sections. <![CDATA[to split the ]]]]><![CDATA[> token ]]>
I test it for qcow2 format. Other formats are TBA. qemu-img resize kvm1.qcow2 +20G cp kvm1.qcow2 kvm1-orig.qcow2 virt-resize –expand /dev/sda1 kvm1-orig.qcow2 kvm1.qcow2 Reference: https://fatmin.com/2016/12/20/how-to-resize-a-qcow2-image-and-filesystem-with-virt-resize/ I test it for qcow2 format. Other formats are TBA. qemu-img resize kvm1.qcow2 +20G cp kvm1.qcow2 kvm1-orig.qcow2 virt-resize –expand /dev/sda1 kvm1-orig.qcow2 kvm1.qcow2 Reference: https://fatmin.com/2016/12/20/how-to-resize-a-qcow2-image-and-filesystem-with-virt-resize/
How to create a file if not exist and open it in read and write modes in C++? For example, I would like open a fstream on /tmp/cache to be able to read it and append to it. If the file does not exist yet, create one. A simple code like std::fstream fs(“/tmp/cache”, std::ios::in |…
C++11 requires that lambda function parameters be declared with concrete types. This is sometimes annoying. auto is really nice, especially when the type is complex like std::vector<std::string>::iterator is quite long to type. I know C++14 allows auto in lambda functions. But how to not use concrete types in lambda function parameters in C++11? In C++11,…
Bash has a -b test to test whether a file exists and is a block special file. -b file True if file exists and is a block special file. How to do this in Python? Python’s stat module provides the similar functions for the C standard APIs and macros underlining such as stat() and S_ISBLK()….
The problem is with ssh that makes a quoted string to more than one if there are spaces. For example, ssh user@host cmd “my string” The cmd on host will be executed like cmd my string rather than cmd “my string” It will only work if the string is escaped like ssh user@host cmd my…
In many text processing tasks, we often need to check if a given string starts with a specific substring. In this article, we will demonstrate how to achieve this using the std::string::compare() function from the C++ Standard Library. The compare() function has several overloads, but the one of interest for our purpose is: int compare(size_type…
How to split and iterate a string separated by a specific character in C++? For example, “a string separated by space” by ‘ ‘=> [“a”, “string”, “separated”, “by”, “space”] and “a,string,separated,by,comma” by ‘,’ => [“a”, “string”, “separated”, “by”, “comma”] C++ standard library’s getline() function can be used to build a function. getline() can accept a…
Admins usually need to generate some passwords for others, such as when creating a new user in a Linux system. How to generate a password in Shell on Linux? Several possible and short methods. Here, we generate a password of length 8. Using pwgen: $ pwgen 8 1 dao3PaW9 Password based on base64 (note that…
How to operator[] access element in a const map in C++? For example, the compiler will report error on this piece of code: #include <iostream> #include <string> #include <map> std::int64_t count(const std::map<std::string, std::int64_t>& map) { return map[“one”] + map[“two”]; } int main () { std::map<std::string, std::int64_t> map = { {“one”, 1}, {“two”, 2} }; std::cout…
Vim seems not indent C++11 lambas very well. How to make Vim indent C++11 lambdas correctly? For this following program, Vim indents it as #include <iostream> #include <string> #include <vector> #include <algorithm> int main () { std::vector<std::string> strs({“one”, “two”}); std::vector<std::string> newstrs; std::transform(strs.begin(), strs.end(), std::back_inserter(newstrs), [](const std::string& s) -> std::string { if (s == “one”) {…
It seems Thunderbird sends out my private/lan IP to the SMTP server. For example, in an Email sent out by Thunderbird, the header contains Received: from [192.168.1.2] (example.com [1.2.3.4]) by mail.example.com (Postfix) with ESMTPSA id 92CD297DEA; It is fine that the SMTP server records the public IP (1.2.3.4) as it is what it sees. But…
How to list start and end of a partition by the sectors in parted on Linux? The default behavior seems be listing the start and end by bytes in parted. # parted /dev/sdc print Model: Innostor IS888 ext. HDD (scsi) Disk /dev/sdc: 2000GB Sector size (logical/physical): 512B/512B Partition Table: gpt Disk Flags: Number Start End…
Evolution seems wrap long lines automatically in “Plain Text” mode. How to make Evolution not wrap lines in composed Emails? Evolution does not have (so far) “Flowing Text” mode where “the text is soft broken at the composer edge, but those soft breaks aren’t translated to hard breaks when the mail is sent” ( Reference:…
Does Evolution support automatic email address filling/completing in the “To” or “CC” fields which is commonly seen in other Email clients such as Thunderbird. Is is possible and how to enable Email address auto completion in Evolution? Evolution supports the contact autocompletion. To enable it, do as follows in Evolution. In Evolution Preferences dialog, in…
Evolution’s default Email sort order is not very convenient, at least to me. How to apply the settings of sort order for a folder to all folders in Evolution? Manually setting the email sort order for each dir is tedious. Evolution has a function to “apply the same view settings to all folder” so that…
How to search history commands very effectively in bash shell command line? Just enter CTRL+r The function of above is: (reverse-i-search)`’: It is very fast and efficient.
How to iterate all dirs and files in a dir in C++? To open a dir, we can use opendir() to open a directory stream. DIR *opendir(const char *name); Then we can use readdir() to iterate the directory stream. struct dirent *readdir(DIR *dirp); Here is an example C++ program using these 2 library functions. #include…
How to check CPU working frequency in iOS on iPhone, such as my iPhone 6? The Litum Info Lite free app (Litum Info full version app) can show you the info of CPU including its frequency. The CPU frequency: You can find the CPU info page from the menu:
How to get a path’s mtime in C++ on Linux? The path can be a file or a dir. You may call the standard library function lstat() for the file or dir under the path. int lstat(const char *pathname, struct stat *statbuf); From the returned stat struct, there is a field st_mtim which is the…