How can I use a variable in sed?


 
Thread Tools Search this Thread
Top Forums Shell Programming and Scripting How can I use a variable in sed?
# 1  
Old 05-27-2004
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  
Old 05-27-2004
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:
# 3  
Old 05-27-2004
Computer

Thanks for excelent answers !! It works....
Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

How to use the variable in sed?

version=git release=r8 echo lp-testsuite-git-r8.x86_64.rpm |sed -e "s/-$version-$release.*//g" I want to get lp-testsuite what's wrong with me ? (1 Reply)
Discussion started by: yanglei_fage
1 Replies

2. Red Hat

How to pass value of pwd as variable in SED to replace variable in a script file

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: ... (6 Replies)
Discussion started by: cielle
6 Replies

3. Shell Programming and Scripting

sed with variable

Hi Friends in sed whether we can use variable.like the following expression. sed -i 's/ABC/$var/g' filename I am using Kernel 2.6.18-194.11.1.el5 RedHat linux. I have tried sed -i 's/ABC/"$var"/g' filename, still not working.:( Please help. Thanks in advance Joy (2 Replies)
Discussion started by: itsjoy2u
2 Replies

4. Shell Programming and Scripting

Expand an environment variable in sed, when the variable contains a slash

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... (2 Replies)
Discussion started by: Ilja
2 Replies

5. Shell Programming and Scripting

Insert a line including Variable & Carriage Return / sed command as Variable

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... (2 Replies)
Discussion started by: lowmaster
2 Replies

6. Shell Programming and Scripting

using variable in sed

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. (3 Replies)
Discussion started by: Kochu77
3 Replies

7. Shell Programming and Scripting

Sed variable substitution when variable constructed of a directory path

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... (2 Replies)
Discussion started by: alrinno
2 Replies

8. Shell Programming and Scripting

sed with a variable

Hi, My shell script searches a VALUE in a file, copies it to a variable and updates a line in another file with this new VALUE (replacing the old) The value has a pattern- VALUE=`$$MyDate=11-11-2008 09.09.56.123456` (yes the $ - . = and space are all part of the string) I am having... (6 Replies)
Discussion started by: ngagemaniac
6 Replies

9. Shell Programming and Scripting

sed (variable)

HOw can I use any variable in sed command. For example I am using 'sed -e 's/?/$ORACLE_HOME/g' $file_name Here it replaces ? with $ORACLE_HOME. Instead of it I need actual value of $ORACLE_HOME. How can I do that? Please advice. Thanks in advance. Malay (13 Replies)
Discussion started by: malaymaru
13 Replies

10. UNIX for Dummies Questions & Answers

Doing a sed on a variable help !

Hi, So what I'm trying to do is I have these variables and if they have a dot in them , I want everyting before and including the dot removed. Any ideas ? Something like this I would want : $var = $var | sed 's/.*\.//' but that does't work. I want to save that removal $var... (2 Replies)
Discussion started by: seaten
2 Replies
Login or Register to Ask a Question