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How to find the value of a variable in SED?
Note that your original version contains single quotes around the sed string, which doesn’t insert the value of $line. It is trying to look for the literal line after the end of the line $ (which will never find anything). Since you are looking for the value of the variable in $line, you need to do an eval to get this.
How to search and replace variables in a file?
But I need to modify only the variables which are present in variable_list file and leave others as it is. The first sed expression escapes the $ which is a regex metacharacter. The second extracts just the variable name, then we use indirection to get the value in our current shell and use it in the sed expression.
How is a filter implemented in SED Stack Overflow?
Build a filter dynamically. The filter is implemented internally as a trie data structure, which gives us a lex -like state machine which matches the entire dictionary at once as the input is scanned. For simplicity, we include the $ { and } as part of the variable name.
Do you need to export a variable in Bash?
Since you are looking for the value of the variable in $line, you need to do an eval to get this. Also, since there are multiple variables you are looping over, the intermediate text variable stores the result as it loops. The export keyword is also unnecessary in this script, unless it is being used in some sub-process not shown. TXR solution.
How to replace a variable in a shell script?
Hello everyone, In one of my shell script I am doing sed/replace using a variable to find a string in a file & replace it with another string in same file. The challenge which I am facing is that, the variable which I am using with “sed” is having one of character as “/” Here is below how… 3. Shell Programming and Scripting
How to change the value of a variable?
Example: Filename : abc.txt contents: a=10 b=20 c=30 Need to change the value of, say, b – Tried using the following: sed “s/$ {b}/15/g” abc.txt Have tried various forms of sed (with single quotes,… 5. Red Hat Hi all, Hereby wish to have your advise for below: Main concept is I intend to get current directory of my script file.
How to replace whole line with SED loop?
So if you set the pattern “Revision: 1190” it’s obviously not the same as you defined them as “Revision:” only… find_replace file contains 2 columns, c1 with pattern to match, c2 with replacement, the sed loop replaces each line conatining one of the pattern of variable 1
Can you use sed to edit lines in a file?
I was looking at this solution: Using sed to edit lines in a file with a variable and tried to apply it to my situation, but I have only recently discovered sed and haven’t got the hang of it yet. If I have a file located /tmp/mary.txt and it looks like this: