If you’ve got a string of items in bash which are delimited by a common character (comma, space, tab, etc) you can split that into an array quite easily. Simply (re)define the IFS variable to the delimiter character and assign the values to a new variable using the array=($<string_var>) syntax. The new variable will now [...]
Posts Tagged ‘string’
Convert a delimited string into an array in Bash
Posted: 9th March 2012 by Tim in BashTags: array, Bash, delimiter, IFS, linux, OIFS, script, scripting, string, terminal, unix
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Reading from a file in C
Posted: 31st October 2010 by Tim in CTags: C, fgets, file, file handling, getline, input, program, read, string
Reading data from a file is fairly common. The stdio.h provides us with a function, getline, which allows us to read lines from a file without worrying about buffer overflows and other memory corruption issues that C is famous for. The following code opens a file named “myfile.txt” and prints out each line with the [...]
Substrings in Bash
Posted: 17th October 2010 by Tim in BashTags: Bash, manipulation, programming, script, shell, string, substr, substring, variable
There are a number of ways to extract parts of a string in bash. If you know the position of the substring you’re looking for, then you can use the ${string:offset[:length]} syntax. This works by providing a string, an offset (or starting position – remember that the first letter is in position 0) and, optionally, [...]
Reading from a file in C++
Posted: 27th September 2010 by Tim in C++Tags: C, config, file, fstream, ifstream, input, read, reading, string, txt
Reading data from a file is common in programming. C++ makes this process fairly painless with the ifstream class. When combined with the string class, you can avoid the memory and buffer overflow issues which you would have to deal with in C. The following example opens a file named “myfile.txt” and prints out each [...]
Concatenation in PostgreSQL
Posted: 15th June 2010 by Tim in PostgreSQLTags: concat, concatenation, database, PostgreSQL, result, server, SET, sql, string
It’s often useful to concatenate two fields together in an SQL query. In PostgreSQL, fields may be concatenated using the || operator. The syntax is really simple. Just place the double bar between the fields you want to join, and (optionally) give a label to that new field. Strings can also be concatenated with the [...]
Checking for empty string in Bash
Posted: 19th May 2010 by Tim in BashTags: Bash, coding, dash, empty, language, linux, null, programming, script, scripting, SET, shell, string, terminal
In Bash you quite often need to check to see if a variable has been set or has a value other than an empty string. This can be done using the -n or -z string comparison operators. The -n operator checks whether the string is not null. Effectively, this will return true for every case [...]