How to pass variables from Bash to SED?

How to pass variables from Bash to SED?

It basically appends TXT_NEW after TXT with the define variables. Running the script wrapped in a small bash script throws an error: In order to trouble shoot i echoed the sed command using as follows: And i see the variables expand correctly like this: Appreciate if someone can have a look and provide some pointers…

Is there a way to do somthing in SED?

You can do that by escaping all the problematic characters in the variable, so that sed takes them literally. And, this escaping can be done using sed as well. If you’re using BREs (Basic Regular Expressions) (the default in sed), you can do somthing like this:

When to use single quotes or double quotes in SED?

The shell is responsible for expanding variables. When you use single quotes for strings, its contents will be treated literally, so sed now tries to replace every occurrence of the literal $var1 by ZZ. Using double quotes. Use double quotes to make the shell expand variables while preserving whitespace:

Do you need a temp variable in SED?

I want to parse these into a variable called LAT and LON which I’m trying to do via sed like so This can be solved via pure shell syntax. It does require a temp variable because of the parentheses (brackets) though: Alternatively, you can do it in one go by playing with IFS and using the read builtin:

How to use sed with command line argument?

You can sed “s/$1/pitt/g” or sed ‘s/’$1’/pitt/g’. or, if the command line argument is not a simple word, sed ‘s/'”$1″‘/pitt/g’.

When to use Eval instead of SED in Bash?

If you don’t trust your inputs, don’t use #2 UPDATE: The comments are right, there is no benefit to using eval (I used to use eval with sed this way all the time, and I’m not sure why….) building sed strings for later use, however, is powerful: so I’ll add a new 3) and leave 2 for folks to mock Thanks for contributing an answer to Stack Overflow!

How can I use sed without removing the quotes?

While this command is working, what I would like to know is how can I do this command without removing the quotes, since I might have some content in the replacement string which needs the quotes. I am not so confident with the quotes and that is why I want to see how things will work with a little tweaking?

How to avoid escaping characters when passing a variable to SED?

You can avoid this by either escaping certain characters: but it is easy to miss this. The safest way, in my opinion, is to surround the variables with double quotes (so that spaces don’t brake the sed command) and surround the rest of the string with single quotes (to avoid the necessity of escaping certain characters):

Do you need to use sed to read from a file?

If your requirement is really something like above, you need not use sed. cat file1 file2 will do 🙂 . 1. Write the lines from 2nd to 4th to a file, say file2. The option ‘2,4w’ indicates to write the lines from 2 to 4. What is the option “-n” for?

Why is the r command failing in SED?

First of all, you have a problem with double quoting. Single quotes inside outer double quotes are making sed fail, since it’s reading the first character ‘ as an invalid command. The r command is similar to a (append text), but it reads the text to be appended from the file specified.

When to use apostrophes in a sed command?

Also, you might want to replace * with *.php, or make backups (pass an argument after -i, and it will make a backup with the given extension). You are using Unicode apostrophes (RIGHT SINGLE QUOTATION MARK – U2019) instead of ASCII (0x27) apostrophes around your sed command argument.

Why does SED exit with error code 4?

It’s normal behavior. In both cases sed exits with error code 4 per info sed: 4 An I/O error, or a serious processing error during runtime, GNU ‘sed’ aborted immediately. and in both cases the messages are self-explanatory.

How to read output of SED into a variable?

The % in the last example will ensure only the last .txt is replaced. If it should be allowed that the filename in $a has more than one occurrence of .txt in it, use the following solution. Its more safe.

What can you do with sed command in Perl?

The word, ‘Bash’ exists in the text. So the output is ‘Perl Scripting Language’. `sed` command can be used to substitution any part of a file content also. Create a text file named weekday.txt with the following content.

How to add backslash to file path in SED?

The following command of `sed` will add backslash (\\) in the file path. The file path, ‘/home/ubuntu/code/perl/add.pl’ is provided as input in the `sed` command and the following output will appear after running the above command. 8. Replace all files full path with just the filename no directory

Which is a better programming language, AWK or SED?

Awk is a more complete programming language, and supports named variables, unlike sed. The -v option allows you to pre-load an awk variable with the contents of a shell variable. CSH is considered harmful by some.

When to use quote in a sed command?

When you require the quote character in the replacement string, you have to precede it with a backslash which will be interpreted by the shell. In the following example, the string quote me will be replaced by “quote me” (the character & is interpreted by sed):