Today (Saturday) We will make some minor tuning adjustments to MySQL.

You may experience 2 up to 10 seconds "glitch time" when we restart MySQL. We expect to make these adjustments around 1AM Eastern Daylight Saving Time (EDT) US.


How can I use a variable in sed?


Login or Register to Reply

 
Thread Tools Search this Thread
# 1  
How can I use a variable in sed?

Hi
I'm trying to change a part of a line with sed. Usually I will run
sed 's/mytext/mynewtext/'

Now I have a variable: var=mynewtext

sed 's/mytext/$var/' does not work. I have also tried to protect the $ with different characters but it still does'nt work.

I will be very happy if someone has a solution to this.
# 2  
For starters, you can switch to double quotes:

sed "s/mytext/$var/"

Sometimes that does not work. It would depend on the exact value of mytext. So another solution is to turn the single quoted string into two single quoted strings:

sed 's/mytext/'$var'/'

In this case, the 2nd single quoted string is '/'. Just using a backslash would work to that and it saves a character:

sed 's/mytext/'$var\/

There is actually no reason to quote a slash so this should also work with most shells:

sed 's/mytext/'$var/

And there may be no reason to quote anything at all, but again, the actual vakue of mytext determines this. So this may work:

sed s/mytext/$var/

Opps...you only wanted a solution, so I'll quit now....Smilie
These 3 Users Gave Thanks to Perderabo For This Post:
Login or Register to Reply

|
Thread Tools Search this Thread
Search this Thread:
Advanced Search

More UNIX and Linux Forum Topics You Might Find Helpful
How to pass value of pwd as variable in SED to replace variable in a script file
cielle
Hi all, Hereby wish to have your advise for below: Main concept is I intend to get current directory of my script file. This script file will be copied to /etc/init.d. A string in this copy will be replaced with current directory value. Below is original script file: ...... Red Hat
6
Red Hat
Expand an environment variable in sed, when the variable contains a slash
Ilja
I'm trying to make a sed substitution where the substitution pattern is an environment variable to be expanded, but the variable contains a "slash". sed -e 's/<HOME_DIRECTORY>/'$HOME'/'This gives me the following error: sed: -e expression #1, char 21: unknown option to `s'Obviously this is...... Shell Programming and Scripting
2
Shell Programming and Scripting
Insert a line including Variable & Carriage Return / sed command as Variable
lowmaster
I want to instert Category:XXXXX into the 2. line something like this should work, but I have somewhere the wrong sytanx. something with the linebreak goes wrong: sed "2i\\${n}Category:$cat\n" Sample: Titel Blahh Blahh abllk sdhsd sjdhf Blahh Blah Blahh Blahh Should look like...... Shell Programming and Scripting
2
Shell Programming and Scripting
using variable in sed
Kochu77
i need to use a value in the Variable to print a particular line from a file using sed command. i tried the below one but its is not working sed -n ' "$var"p ' abc.txt but its is not working please help me to sort out this.... Shell Programming and Scripting
3
Shell Programming and Scripting
Sed variable substitution when variable constructed of a directory path
alrinno
Hello, i have another sed question.. I'm trying to do variable substition with sed and i'm running into a problem. my var1 is a string constructed like this: filename1 filerev1 filepath1 my var2 is another string constructed like this: filename2 filerev2 filepath2 when i do...... Shell Programming and Scripting
2
Shell Programming and Scripting

Featured Tech Videos