#Linux substitute for basic notepad code#

i option is used to edit in place on the file hello.txt. The following two options (flags) are combined into one, -ie: This is useful in some circumstances, like altering special characters at the beginnings of lines (for instance, replacing the greater-than symbols some people use to quote previous material in email threads with a horizontal tab while leaving a quoted algebraic inequality later in the line untouched), but in your example where you specify that anywhere few occurs it should be replaced, make sure you have that /g. If you leave off the /g (with s/few/asd/, there always needs to be three slashes no matter what) and few appears twice on the same line, only the first few is changed to asd: g stands for 'global', meaning to do this for the whole line. S/ is used to substitute the found expression few with asd: Sed is the stream editor, in that you can use | (pipe) to send standard streams (STDIN and STDOUT specifically) through sed and alter them programmatically on the fly, making it a handy tool in the Unix philosophy tradition but can edit files directly, too, using the -i parameter mentioned below.Ĭonsider the following: sed -i -e 's/few/asd/g' hello.txt Python can also have regular expressions, in particular, there's re module, which has re.sub() function, which can be used for more advanced replacements.

myscript.py is in your current working directory and for the first way, ensure it is set executable with chmod +x. The exact command to run python script with command-line argument would be $. This script is to be called with input.txt as command-line argument. With open(sys.argv) as fd1, open(tmp,'w') as fd2: For instance, here's a simple one: #!/usr/bin/env python With Python, however, you also need to output to new file, which you can also do from within the script itself. Simple way to read file and replace string in it would be as so: python -c 'import sys lines=() print lines.replace('blue','azure')' < input.txt It has a lot of functions for working with strings, among which is replace(), so if you have variable like var='Hello World', you could do var.replace('Hello','Good Morning') This language is very versatile and is also used in a wide variety of applications. Simple substitution can be done as so: perl -pe 's/blue/azure/' input.txt It borrowed a lot of concepts/features from other languages such as C,sed,awk, and others. Perl is another tool which is often used for text processing, but it's a general purpose language, and is used in networking, system administration, desktop apps, and many other places. What's good about this tool is that it has in-place editing, which you can enable with -i flag. It also uses regular expressions, but for simple substitutions it's sufficient to do: sed 's/blue/azure/' input.txt This is an input.txt and this doesn't rhymeīash isn't really meant for text processing, but simple substitutions can be done via parameter expansion, in particular here we can use simple structure $'

The file contents: roses are red, violets are blue In this answer I am using simple input.txt file, which you can use to test all examples provided here. Depending on the complexity of what one tries to achieve with string replacement, and depending on tools with which user is familiar, some methods may be preferred more than others.

The most suitable solution I can think of with the given assumptions of the problem.There's multitude of ways to achieve it. This kind of parsing should be slower than one-hit search and replace but, as you already saw, there are four variables for four different search patterns working out of one parse cycle. ServerName which becomes linux substitute for basic notepad

The BashFAQ seems to agree with what I understand at least. When my restriction is to use it in a shell script, no variable can be used inside in place of 'abc' or 'XYZ'.

#Linux substitute for basic notepad code#

Look at this code from sed -i -e 's/abc/XYZ/g' /tmp/file.txt I found this thread among others and I agree it contains the most complete answers so I'm adding mine too: