Using variables in a sed command - linux

I'm trying to add some text (a path) at the end of a line which is found by a sed command:
var="/folder1/folder2/folder3"
sed -i "/Begins with this text/s/$/$var/" filename
I know that double quotes are needed to use variables in a sed command but if I use the above command it gives me an error message saying:
expresssion #1, character 23: unknown option to `s
What am I doing wrong?

Change the delimiter in the substitute command to something that won't appear in $var, e.g.
sed -i "/Begins with this text/s|$|$var|" filename
or escape the slashes in $var:
var="\/folder1\/folder2\/folder3"

Related

Sed command fails with an unterminated `s' command as part of shell script, but not when run separately [duplicate]

I run below sed command
sed -i s/abc=.*$/abc=def ghi/g hpq_sf_attach_wf_param.txt
and it gave me error:
sed: -e expression #1, char 17: unterminated `s' command
I noticed it is due to space in between of def and ghi.
Any idea how to fix it?
You need to use quoting to protect special characters, including spaces, $, and *.
sed -i 's/abc=.*$/abc=def ghi/g' hpq_sf_attach_wf_param.txt
So geekosaur had it right. The the reason you had the problem though is because it needs to be double quotes for the wildcards because with single quotes it takes them as literal characters, not for the meaning you want.
sed -i "s/abc=.*$/abc=def ghi/g" hpq_sf_attach_wf_param.txt
Also if the space between "def" and "ghi" gives you problems, adding a "\" should help making it read it as a literal space.
sed -i "s/abc=.*$/abc=def\ ghi/g" hpq_sf_attach_wf_param.txt

sed command to replace 'root'#'localhost' with 'root'#'%'

I am trying to use sed to replace the expression 'root'#'localhost' with 'root'#'%' with no success. Could someone please help me with the command?
I tried the following:
sed -i ’s#\’root\’#\’localhost\’#\’root\’#\’%\’#g’ xyz.sql
sed: -e expression #1, char 1: unknown command: `?'
sed -i -e ’s/localhost/%/g’ xyz_2616.sql
sed: -e expression #1, char 1: unknown command: `?'
First, make sure you're using a single quote. ’ (a.k.a. ’ or unicode 8217) is not the same as ASCII character 39, '.
Next, you can't escape single quotes inside single quotes. Here's an answer I wrote about that some time ago.
You can, however, put single quotes inside double quotes, or escape them outside your single quoted string. For example, either of the following might work:
sed -e "s/'root'#'localhost'/'root'#'%'/g" file.sql
or
sed -e 's/'\''root'\''#'\''localhost'\''/'\''root'\''#'%'\''/g' file.sql
Alternately, you could substitute just the portion you're interested in, trusting that it doesn't appear elsewhere on the same line:
sed -e '/root.#.localhost/s/localhost/%/' file.sql
The ’ character doesn't look like a single quote (') to me. Make sure that you are using single quotes.
The character you're actually typing is a "right single quote mark". What we refer to as a "single quote" is actually an "apostrophe".
The following should work:
sed -e 's/localhost/%/g' rice_2616.sql
or, your first alternatives but with double quotes to avoid having to escape the embedded single quotes (which I presume are apostrophes):
sed -e "s/'root'#'localhost'/'root’#'%'/g" rice_2616.sql

How do I find and replace text using sed using ~ as delimiter

Good-day,
In a Bash shell script I'm putting together, I am trying to find this text: /usr/local/freeswitch/log/freeswitch.log and replace it with: /var/log/freeswitch/freeswitch.log in this file: /etc/fail2ban/jail.local
This is what I have tried so far, both of which result in the error: sed: -e expression #1, char 75: unterminated `s' command
Attempt #1
sed -i 's~usr/local/freeswitch/log/freeswitch.log~var/log/freeswitch/freeswitch.log' /etc/fail2ban/jail.local
Attempt #2
sed -i 's~usr/local/freeswitch/log/freeswitch.log/var/log/freeswitch/freeswitch.log' /etc/fail2ban/jail.local
My research shows that since the text I'm searching for includes the "/" character, I should be using a different delimiter "~" to separate the find and replace strings. But looks like I'm doing something wrong, any assistance would be appreciated, thanks.
The structure of a sed substitution command is s/PATTERN/REPLACEMENT/ (note the delimiter at the end of the command).
You're right, you can change the delimiter to a different character, so if you're going to use ~ you need to put one of those at the end of the command.

How to use sed with a variable that needs to be escaped

I have a file, and I am trying to use bask to replace all the contents of a substring with a path.
I can use the command:
sed -i s/{WORKSPACE}/$MYVARIABLE/g /var/lib/jenkins/jobs/MY-JOB/workspace/config/params.ini
My config/params.ini looks like:
[folders]
folder1 = {WORKSPACE}/subfolder1
folder2 = {WORKSPACE}/subfolder2
however, when $MYVARIABLE is a path, it fails (containing slashes), the sed command fails with:
sed: -e expression #1, char 16: unknown option to `s'
When I run through it manually, I see that the $MYVARIABLE needs to have it's path-slashes escaped. How can I modify my sed command to incorporate an escaped version of $MYVARIABLE?
There's nothing saying you have to use / as your delimiter. sed will use (almost) anything you stick in there. I have a tendency to use |, since that never (rarely?) appears in a path.
sridhar#century:~> export boong=FLEAK
sridhar#century:~> echo $PATH | sed "s|/bin|/$boong|g"
~/FLEAK:/usr/local/FLEAK:/usr/local/sbin:/usr/local/games:/FLEAK:/sbin:/usr/FLEAK:/usr/sbin:/usr/games:/usr/lib/lightdm/lightdm:/home/oracle/app/oracle/product/12.1.0/server_1/FLEAK
sridhar#century:~>
Using double-quotes will allow the shell to do the variable-substitution.
Just escape the $ sign, and use a different delimiter:
sed -i 's;{WORKSPACE};\$MYVARIABLE;g' your_file

How to use variable in sed command to replace a property value in a property file

i can able to use the below command to change value of target by means of hard coding.
sed -ie s/^target=.*/target=google.com/ url.properties
But if i used variable i am getting error. I dont know how sed commands all working. I only needed to set build system thats it.
url = google.com
sed -ie s/^target=.*/target=$url/ url.properties
the error is
sed: -e expression #1, char 25: unterminated `s' command
The problem may be happening because your URL may contain / which bash interprets as sed syntax, so something like https/www.google.com ends up something like :
sed -ie 's/^target=.*/target=https/www.google.com/' url.properties
I will suggest to delimit any special characters to avoid sed to be confused :
url=google.com
url=`echo $url | sed -e "s/\//\\\\\\\\\//g"` # delimits backslash in URL's
sed -ie "s/^target=.*/target=$url/" url.properties
Two problems:
You can't have spaces in variable assignments in bash
You must quote the sed command (and ideally the url too)
Working example:
url="google.com"
sed -ie "s/^target=.*/target=$url/" url.properties

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