But if, as you say, you're replacing one number with another, that shouldn't be a problem. Not specific to the question, but for folks who need the same kind of functionality expanded for clarity from previous answers:. Found a graceful solution. Single quotes are very strong. Once inside, there's nothing you can do to invoke variable substitution, until you leave. Use double quotes instead:. I had a similar requirement to this but my replace var contained an ampersand.
Escaping the ampersand like this solved my problem:. Not related to question but in case if someone is passing the string as an argument to bash script this might help. For your reference. I prefer to use double quotes , as single quptes are very powerful as we used them if dont able to change anything inside it or can invoke the variable substituion. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams?
Collectives on Stack Overflow. Learn more. Replace a string in shell script using a variable Ask Question. Asked 11 years, 5 months ago. Active 20 days ago. Viewed k times. I am using the below code for replacing a string inside a shell script. Could anybody tell what went wrong? Improve this question. Vijay Vijay For the common related question about handling values with slashes in them, see stackoverflow.
Here we also discuss the introduction and how linux sed replace command works? You may also have a look at the following articles to learn more —. Submit Next Question. By signing up, you agree to our Terms of Use and Privacy Policy.
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Email ID. Contact No. It will load the minimal amount of data from the input files and flush the output buffers. Asked 12 years, 5 months ago. Active 7 days ago. Viewed 2. Improve this question. Flimm k 35 35 gold badges silver badges bronze badges. So in the above example, tr could work.. But would be limiting later on. The replacement of newlines is uniquely arcane for sed but easily done by tr. This is a common question.
Performing regex replacements is not done by tr but by sed , which would be the right tool For that I recommend you use "sed" which doesn't have that difference. MikeS Thanks for the answer. Otherwise the last linefeed in the file is deleted, too. Show 7 more comments. Active Oldest Votes. Although it can do what you need. Improve this answer. Ayman Salah 12 12 silver badges 32 32 bronze badges.
I cannot understand why sed cannot do it. Please, clarify to use different tool. Sed is line-based therefore it is hard for it to grasp newlines. Alexander: Does "stream editor" mean line-based? Perhaps, the name is confusing. It is a unix tool, which means it does one thing very well. The one thing is "work on a file line-wise". Making it do something else will be hard, and risks being buggy. The moral of the story is: choose the right tool.
A great many of your questions seem to take the form "How can I make this tool do something it was never meant to do? GNU sed supports changing the "record" separator to null byte instead of newline. Show 3 more comments. Explanation: sed starts by reading the first line excluding the newline into the pattern space. Create a label via :a. Append a newline and next line to the pattern space via N. This is necessary to avoid executing N again, which would terminate the script if there is no more input!
Finally the substitution replaces every newline with a space on the pattern space which is the whole file. Zsolt Botykai Zsolt Botykai You can run this cross-platform i. See number 3 above. This is an impressive answer. I also find it ironic that Linux tools are supposed to be "do one thing well" when it seems like most Linux tools do many things, poorly — Andy Ray.
Long answer from the sed FAQ 5. Community Bot 1 1 1 silver badge. The best part about this answer is that the "long answer" explains exactly how and why the command works. This may be the most helpful of the thousands of answers I've read on stackexchange. I need to match multiple characters across lines.
No previous sed examples covered multi-lines and tr can't handle multiple character matching. Perl looks good, but isn't working as I expect. I'd vote this answer up several times if I could. Show 6 more comments. Thor Thor 41k 10 10 gold badges silver badges bronze badges. A conditional could also be added to this expression, e. When using awk like this then, unfortunately, the last line feed in the file is deleted, too. Jonah: this is an alternate way of setting variables, see e.
Show 2 more comments. GNU sed has an option, -z , for null-separated records lines. Peter Mortensen JJoao JJoao 4, 1 1 gold badge 16 16 silver badges 19 19 bronze badges. Even if the input does contain nulls, they will be preserved as record delimiters. Won't this load the whole input if there're no nulls?
In this case processing a multi-gigabyte file may be crashy. Ruslan, yes it loads the whole input. This solution is not a good idea for multi-gigabyte files. This is seriously the best answer. The other expressions are too contorted to remember. JJoao You can use it with -u, --unbuffered. The man mage states: "load minimal amounts of data from the input files and flush the output buffers more often".
Ruslan If you have a multi-gigabyte textfile, you don't want to use sed anyway, even in line-based mode, as sed is annoying slow on large input. Show 5 more comments. Please at least mention that -i without a suffix makes no backup. Telemachus: It's a fair point, but it can be argued either way.
The main reason I didn't mention it is that the sed example in the OP's question doesn't make backups, so it seems superfluous here.
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