This question already has answers here:
Shell variables in sed script [duplicate]
(5 answers)
Closed 8 years ago.
I want to delete words into a line. For example:
I want to delete one word in this line
And I want to delete 'one' to obtain:
I want to delete word in this line
By passing the word through a variable. So far I have got:
WORD=one ; sed -n 's/"$WORD"//g' file.txt > newfile.txt
But, it doesn't do anything. Why not? And how can I make it work?
WORD=one ; sed -e "s/$WORD//g" file.txt > newfile.txt
the key moment is variable expansion. You have to be careful though because shell variable expansion may be sometimes not what you want. In hard cases you have to do something like this:
EXPANDVAR=one; NOEXPANDVAR=another; sed -e 's/'"$EXPANDVAR"'$NOEXPANDVAR//g' file.txt > newfile.txt
In this case sed will replace (remove) pattern one$NOEXPANDVAR , literally.
Related
This question already has answers here:
How do I replace single quotes with another character in sed?
(6 answers)
Closed 5 months ago.
Trying to put ' before each line of text and ' at the end of each line of text.
I have been using sed 's/^/1/' file.txt to replace to begging of each line and sed 's/$/0/' file.txt to replace the end of each line.
What I am trying to make work is sed 's/^/'/' and sed 's/$/'/'
This would format my file to make each line reach as a command, when applied to a separate script.
echo abc | sed "s/.*/'&'/"
Output:
'abc'
From man sed:
The replacement may contain the special character & to refer to that portion of the pattern space which
matched
This question already has answers here:
How to replace a whole line with sed?
(6 answers)
Closed 1 year ago.
hello I am needing help to be able to replace a line of a file with ssh and sed.
The problem is the following I have a string for example:
mystring = 1234
The point is that after the = it is not always 1234, so I am not able to replace that line.
sed -i 's/mystring =/mystring=1234/g' file.ini
when I run it two things happen:
mystring = 12341234 (add the numbers)
mystring = 123412345 (don't delete it, leave it there)
and if the variable (sed -i 's/mystring=/mystring=1234/g' file.ini) is executed more than twice, what it does is add the number at the end.
That is why I need to replace the entire line, something that if it is done more than 1 you see it will always remain the same, and if it is different, change it to the value that is set in the command.
From already thank you very much.
You can always match and replace the whole line:
sed -i 's/^mystring=.*/mystring=newvalue/' yourfile
.* in a regular expression matching any number of characters, including none.
You can also change all lines containing a certain pattern:
sed -i '/^mystring=/c\
mystring=newvalue' yourfile
Or with GNU sed:
sed -ie '/^mystring=/c\' -e 'mystring=newvalue' yourfile
This question already has answers here:
How to escape the ampersand character while using sed
(3 answers)
Closed 2 years ago.
My config file looks like:
KEY1=VALUE1
URL=https://drive.google.com/uc?export=download&id=myhash
KEY3=VALUE3
I'm trying to use sed to replace the URL value with another one. I got to the following:
sed -i.bak 's#URL=.*#URL=https://drive.google.com/uc?export=download&id=mynewhash#g' file.txt
But that doesn't seem to work, as I'm getting:
URL=https://drive.google.com/uc?export=downloadURL=https://drive.google.com/uc?export=download&id=mynewhash=myhash
What am I missing? Thanks
& is a special character in the replacement string provided to the s command of sed. It represents the string that matches the entire regex used to search (URL=.* in your example).
In order to represent itself it needs to be escaped with \:
sed -i.bak 's#URL=.*#URL=https://drive.google.com/uc?export=download\&id=mynewhash#g' file.txt
Type man sed in your terminal to read its documentation or read the documentation of sed online.
This question already has answers here:
How to make sed remove lines not matched by a substitution
(4 answers)
Boolean OR in sed regex
(4 answers)
Closed 4 years ago.
How can I keep all lines matching all those words
toto OR titi OR clic OR SOMETHING and delete any other lines?
If I do sed '/toto/ p ' file I cannot select titi for example.
What I am looking for is something similar to a Perl Regular expression as
^ (word1|word2|word3|andsoon).*. However, I need it for sed because it will be integrated into a bigger sed script.
The goal is to keep all lines starting with word where word is any word from a set of words.
The answer here depends a bit on how your master script is called. Imagine you have a file with the following content:
foo
car
bar
and you are interested in the lines matching "foo" and "bar", then you can do:
sed '/foo\|bar/!d'
sed -n '/foo\|bar/!d;p'
sed -n '/foo\|bar/p'
all these will output:
foo
bar
If you would just do:
sed '/foo\|bar/p'
you actually duplicate the lines.
foo
foo
car
bar
bar
As you see, there is a bit of different handling depending on the usage of the -n flag.
-n, --quiet, --silent suppress automatic printing of pattern space
source: man sed
In general, my suggestion is to delete the lines you don't need at the beginning of your sed script.
This question already has answers here:
Remove everything after the first / including the first / for each line
(3 answers)
Closed 8 years ago.
I'm trying to use command line to find and replace some text. I have a file with a few million lines that are similar to this:
Something-Here/Grafton-WV</loc>
More-Information/Claremore-OK</loc>
This-Is-It/Seminole-OK</loc>
Your-Company/Lunenburg-MA</loc>
What I need to do is remove the slash and everything after it. I've done wildcard find/replace before but I'm not sure what command would need to be used to start at the slash and continue until the end of the line.
Here's what the output should be:
Something-Here
More-Information
This-Is-It
Your-Company
The following one-liner could work for you:
perl -pe 's{/.*}{}' file.txt
Explanation:
Switches:
-p: Creates a while(<>){...; print} loop for each “line” in your input file.
-e: Tells perl to execute the code on command line.
Code:
s{/.*}{}: Remove all characters after the first forward slash from the line
This is usually done with sed:
sed 's|/.*||' file.txt > newfile.txt