Using a variable in sed command Post: 302985164

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Top Forums Shell Programming and Scripting Using a variable in sed command Post 302985164 by Don Cragun on Monday 7th of November 2016 04:17:21 AM

11-07-2016

Registered User

Quote:

Originally Posted by rahulsk

Hi All,

Please help me with the below problem

Code:

if [ "$a" == "RAHUL" ]
then
$a=" "
fi

echo "ABC1abc" | sed 's/a/'$a'/'

The required output is :

Code:

ABC abc

But I am getting the below error:

Code:

sed: -e expression #1, char 4: unterminated `s' command

Please help.

I don't understand what you're trying to do. Why would a script that attempts to use a sed substitute command to replace the 1st occurrence of the character a with the contents of an undefined variable be expected to change the digit 1 in your sample input to a <space> character???

If you want to change the 1st occurrence of the digit 1 on each input line to the value you have assigned to the shell variable a (assuming that $a does not expand to a string containing any /, \, &, or NUL characters; you could use:

Code:

a="some string"
echo "ABC1abc" | sed "s/1/$a/"

Note that unless you quote the entire substitute command, you can't include blanks in the substitution string because the shell will see sequences of blanks in the substitute command as field separators; not as data included in the replacement string.

Last edited by Don Cragun; 11-07-2016 at 08:24 PM.. Reason: add missing space between sed and its operand

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