Error while adding line to file using sed command [duplicate] - linux

I'm trying to insert text to the third line in a file using sed, and the syntax I've found on other forums is:
sed -i '' "3i\ text to insert" file
When I use this however, I get an error:
sed: 1: "3i\ text to insert": extra characters after \ at the end of i command
I can't seem to figure out what is causing the problem. I'm using OSX, which is why I have an empty ' ' as my extension.
Thanks!

You should put a newline directly after the \:
sed '3i\
text to insert' file
This is actually the behaviour defined by the POSIX specification. The fact that GNU sed allows you to specify the text to be inserted on the same line is an extension.
If for some reason you need to use double quotes around the sed command, then you must escape the backslash at the end of the first line:
sed "3i\\
text to insert" file
This is because a double-quoted string is processed first by the shell, and \ followed by a newline is removed:
$ echo "abc\
def"
abcdef

On OSX you can use:
sed -i.bak '3i\
text to insert
' file

A one-liner for OSX employing ANSI-C quoting:
sed -i '' '3i\'$'\n''text to insert' file
Adapted from https://stackoverflow.com/a/24299845/901597

Here's how to do it in one line syntax
sed -i '' -e "2s/^//p; 2s/^.*/text to insert/" file
duplicate second line: 2s/^//p;
replace new line with your text: 2s/^.*/text to insert/

This works for me
sed -i '' '3i\
text to insert' file

I've found that I have to insert a \ at the end of the line to be inserted, otherwise it concatenates it at the beginning of the original line. So, if I want to insert a new third line,...
sed -i '' '3i\<br>
New line to be inserted.\<br>
' file

If you want to modify a file of specific file type(.sh in my case) use this command.
sed -i '.sh' '3i\
mymodified text to insert' temp.sh
Make sure you have line break after slash ("\")

To insert text to the first line and put the rest on a new line using sed on macOS this worked for me
sed -i '' '1 i \
Insert
' ~/Downloads/File-path.txt

Related

Add many quotation in sed instruction

I have to update line with value containg many quotation characters
sed -i 's/.*sonar.links.issue.*/property "sonar.links.issue", "http://jra.url"'
I get error there. What should i do to do it correctly?
Your replacement string contains slashes "http://", so you shouldn't use / as the delimiter for this sed command, use # as shellter proposes.
To complete its answer, I would add the "g" flag, at the end of the sed expression, to ensure the subsitution is made on the whole line, and not only on the first match with ".sonar.links.issue.".
sed -i 's#.*sonar.links.issue.*#property "sonar.links.issue", "http://jra.url"#g' file
Try
sed -i 's#.*sonar.links.issue.*#property "sonar.links.issue", "http://jra.url"#' file
IHTH

Inserting string in file in nth line after pattern using sed

I want to insert word after nth line after pattern using sed.
I tied to modify this command but it inserts only in first line after pattern.
sed -i '/myPattern/a \ LineIWantToinser ' myFile
What command should I use to insert for example in third line after pattern?
Easiest way to do it with GNU sed is.. (maybe some direct solution exists!?)
sed -n '/pattern/=' file
to see line where pattern is (grep also can be used here with -n)
then if linenumber+ numoflines is for example 123
sed '123aSOME INSERTED TEXT AFTER THAT LINE' file
where little a is append command (after that line, if i is used will be pre pattern line)
ps. I'm eager to see if #neronlevelu (or other sed Lover) will find some better sed solution.
Edit: i've found it, it seems a for append or i for insert must? be on first position on line when using { with ; inside } like
sed '/pattern/{N;N;N;
a SOME TEXT FOR INSERTING
}' file
sed '/pattern/{N;N;N;i \
Line to add after 3 lines with patterne as starting counter
' YourFile
number of N to add line between pattern and inserted line.
there is no check for end of file or pattern in the 3 lines. (not specified in PO)
A version with bash and ed:
ed -s myFile <<<$'/myPattern/+3a\n LineIWantToinser \n.\nwq'
ed enables us to use the line addressing /myPattern/+3.

Replace whole line containing a string using Sed

I have a text file which has a particular line something like
sometext sometext sometext TEXT_TO_BE_REPLACED sometext sometext sometext
I need to replace the whole line above with
This line is removed by the admin.
The search keyword is TEXT_TO_BE_REPLACED
I need to write a shell script for this. How can I achieve this using sed?
You can use the change command to replace the entire line, and the -i flag to make the changes in-place. For example, using GNU sed:
sed -i '/TEXT_TO_BE_REPLACED/c\This line is removed by the admin.' /tmp/foo
You need to use wildcards (.*) before and after to replace the whole line:
sed 's/.*TEXT_TO_BE_REPLACED.*/This line is removed by the admin./'
The Answer above:
sed -i '/TEXT_TO_BE_REPLACED/c\This line is removed by the admin.' /tmp/foo
Works fine if the replacement string/line is not a variable.
The issue is that on Redhat 5 the \ after the c escapes the $. A double \\ did not work either (at least on Redhat 5).
Through hit and trial, I discovered that the \ after the c is redundant if your replacement string/line is only a single line. So I did not use \ after the c, used a variable as a single replacement line and it was joy.
The code would look something like:
sed -i "/TEXT_TO_BE_REPLACED/c $REPLACEMENT_TEXT_STRING" /tmp/foo
Note the use of double quotes instead of single quotes.
The accepted answer did not work for me for several reasons:
my version of sed does not like -i with a zero length extension
the syntax of the c\ command is weird and I couldn't get it to work
I didn't realize some of my issues are coming from unescaped slashes
So here is the solution I came up with which I think should work for most cases:
function escape_slashes {
sed 's/\//\\\//g'
}
function change_line {
local OLD_LINE_PATTERN=$1; shift
local NEW_LINE=$1; shift
local FILE=$1
local NEW=$(echo "${NEW_LINE}" | escape_slashes)
# FIX: No space after the option i.
sed -i.bak '/'"${OLD_LINE_PATTERN}"'/s/.*/'"${NEW}"'/' "${FILE}"
mv "${FILE}.bak" /tmp/
}
So the sample usage to fix the problem posed:
change_line "TEXT_TO_BE_REPLACED" "This line is removed by the admin." yourFile
All of the answers provided so far assume that you know something about the text to be replaced which makes sense, since that's what the OP asked. I'm providing an answer that assumes you know nothing about the text to be replaced and that there may be a separate line in the file with the same or similar content that you do not want to be replaced. Furthermore, I'm assuming you know the line number of the line to be replaced.
The following examples demonstrate the removing or changing of text by specific line numbers:
# replace line 17 with some replacement text and make changes in file (-i switch)
# the "-i" switch indicates that we want to change the file. Leave it out if you'd
# just like to see the potential changes output to the terminal window.
# "17s" indicates that we're searching line 17
# ".*" indicates that we want to change the text of the entire line
# "REPLACEMENT-TEXT" is the new text to put on that line
# "PATH-TO-FILE" tells us what file to operate on
sed -i '17s/.*/REPLACEMENT-TEXT/' PATH-TO-FILE
# replace specific text on line 3
sed -i '3s/TEXT-TO-REPLACE/REPLACEMENT-TEXT/'
for manipulation of config files
i came up with this solution inspired by skensell answer
configLine [searchPattern] [replaceLine] [filePath]
it will:
create the file if not exists
replace the whole line (all lines) where searchPattern matched
add replaceLine on the end of the file if pattern was not found
Function:
function configLine {
local OLD_LINE_PATTERN=$1; shift
local NEW_LINE=$1; shift
local FILE=$1
local NEW=$(echo "${NEW_LINE}" | sed 's/\//\\\//g')
touch "${FILE}"
sed -i '/'"${OLD_LINE_PATTERN}"'/{s/.*/'"${NEW}"'/;h};${x;/./{x;q100};x}' "${FILE}"
if [[ $? -ne 100 ]] && [[ ${NEW_LINE} != '' ]]
then
echo "${NEW_LINE}" >> "${FILE}"
fi
}
the crazy exit status magic comes from https://stackoverflow.com/a/12145797/1262663
In my makefile I use this:
#sed -i '/.*Revision:.*/c\'"`svn info -R main.cpp | awk '/^Rev/'`"'' README.md
PS: DO NOT forget that the -i changes actually the text in the file... so if the pattern you defined as "Revision" will change, you will also change the pattern to replace.
Example output:
Abc-Project written by John Doe
Revision: 1190
So if you set the pattern "Revision: 1190" it's obviously not the same as you defined them as "Revision:" only...
bash-4.1$ new_db_host="DB_HOSTNAME=good replaced with 122.334.567.90"
bash-4.1$
bash-4.1$ sed -i "/DB_HOST/c $new_db_host" test4sed
vim test4sed
'
'
'
DB_HOSTNAME=good replaced with 122.334.567.90
'
it works fine
To do this without relying on any GNUisms such as -i without a parameter or c without a linebreak:
sed '/TEXT_TO_BE_REPLACED/c\
This line is removed by the admin.
' infile > tmpfile && mv tmpfile infile
In this (POSIX compliant) form of the command
c\
text
text can consist of one or multiple lines, and linebreaks that should become part of the replacement have to be escaped:
c\
line1\
line2
s/x/y/
where s/x/y/ is a new sed command after the pattern space has been replaced by the two lines
line1
line2
cat find_replace | while read pattern replacement ; do
sed -i "/${pattern}/c ${replacement}" file
done
find_replace file contains 2 columns, c1 with pattern to match, c2 with replacement, the sed loop replaces each line conatining one of the pattern of variable 1
To replace whole line containing a specified string with the content of that line
Text file:
Row: 0 last_time_contacted=0, display_name=Mozart, _id=100, phonebook_bucket_alt=2
Row: 1 last_time_contacted=0, display_name=Bach, _id=101, phonebook_bucket_alt=2
Single string:
$ sed 's/.* display_name=\([[:alpha:]]\+\).*/\1/'
output:
100
101
Multiple strings delimited by white-space:
$ sed 's/.* display_name=\([[:alpha:]]\+\).* _id=\([[:digit:]]\+\).*/\1 \2/'
output:
Mozart 100
Bach 101
Adjust regex to meet your needs
[:alpha] and [:digit:]
are Character Classes and Bracket Expressions
This worked for me:
sed -i <extension> 's/.*<Line to be replaced>.*/<New line to be added>/'
An example is:
sed -i .bak -e '7s/.*version.*/ version = "4.33.0"/'
-i: The extension for the backup file after the replacement. In this case, it is .bak.
-e: The sed script. In this case, it is '7s/.*version.*/ version = "4.33.0"/'. If you want to use a sed file use the -f flag
s: The line number in the file to be replaced. In this case, it is 7s which means line 7.
Note:
If you want to do a recursive find and replace with sed then you can grep to the beginning of the command:
grep -rl --exclude-dir=<directory-to-exclude> --include=\*<Files to include> "<Line to be replaced>" ./ | sed -i <extension> 's/.*<Line to be replaced>.*/<New line to be added>/'
The question asks for solutions using sed, but if that's not a hard requirement then there is another option which might be a wiser choice.
The accepted answer suggests sed -i and describes it as replacing the file in-place, but -i doesn't really do that and instead does the equivalent of sed pattern file > tmp; mv tmp file, preserving ownership and modes. This is not ideal in many circumstances. In general I do not recommend running sed -i non-interactively as part of an automatic process--it's like setting a bomb with a fuse of an unknown length. Sooner or later it will blow up on someone.
To actually edit a file "in place" and replace a line matching a pattern with some other content you would be well served to use an actual text editor. This is how it's done with ed, the standard text editor.
printf '%s\n' '/TEXT_TO_BE_REPLACED/' d i 'This line is removed by the admin' . w q | \
ed -s /tmp/foo > /dev/null
Note that this only replaces the first matching line, which is what the question implied was wanted. This is a material difference from most of the other answers.
That disadvantage aside, there are some advantages to using ed over sed:
You can replace the match with one or multiple lines without any extra effort.
The replacement text can be arbitrarily complex without needing any escaping to protect it.
Most importantly, the original file is opened, modified, and saved. A copy is not made.
How it works
How it works:
printf will use its first argument as a format string and print each of its other arguments using that format, effectively meaning that each argument to printf becomes a line of output, which is all sent to ed on stdin.
The first line is a regex pattern match which causes ed to move its notion of "the current line" forward to the first line that matches (if there is no match the current line is set to the last line of the file).
The next is the d command which instructs ed to delete the entire current line.
After that is the i command which puts ed into insert mode;
after that all subsequent lines entered are written to the current line (or additional lines if there are any embedded newlines). This means you can expand a variable (e.g. "$foo") containing multiple lines here and it will insert all of them.
Insert mode ends when ed sees a line consisting of .
The w command writes the content of the file to disk, and
the q command quits.
The ed command is given the -s switch, putting it into silent mode so it doesn't echo any information as it runs,
the file to be edited is given as an argument to ed,
and, finally, stdout is thrown away to prevent the line matching the regex from being printed.
Some Unix-like systems may (inappropriately) ship without an ed installed, but may still ship with an ex; if so you can simply use it instead. If have vim but no ex or ed you can use vim -e instead. If you have only standard vi but no ex or ed, complain to your sysadmin.
It is as similar to above one..
sed 's/[A-Za-z0-9]*TEXT_TO_BE_REPLACED.[A-Za-z0-9]*/This line is removed by the admin./'
Below command is working for me. Which is working with variables
sed -i "/\<$E\>/c $D" "$B"
I very often use regex to extract data from files I just used that to replace the literal quote \" with // nothing :-)
cat file.csv | egrep '^\"([0-9]{1,3}\.[0-9]{1,3}\.)' | sed s/\"//g | cut -d, -f1 > list.txt

Insert newline before first line

I am trying to insert a newline before the first line of text in a file. The only solution i have found so far is this:
sed -e '1 i
')
I do not like to have an actual newline in my shell script. Can this be solved any other way using the standard (GNU) UNIX utilities?
For variety:
echo | cat - file
Here's a pure sed solution with no specific shell requirements:
sed -e '1 s|^|\n|'
EDIT:
Please note that there has to be at least one line of input for this (and anything else using a line address) to work.
A $ before a single-quoted string will cause bash to interpret escape sequences within it.
sed -e '1 i'$'\n'
You could use awk:
$ awk 'FNR==1{print ""} 1' file
Which will work with any number of files.

Surround all lines in a text file with quotes ('something')

I've got a list of directories that contain spaces.
I need to surround them with ' ' to ensure that my batch scripts will work.
How can one surround each new line with a ' and a ' (quotes).
e.g.
File1:
/home/user/some type of file with spaces
/home/user/another type of file with spaces
To
File2:
'/home/user/some type of file with spaces'
'/home/user/another type of file with spaces'
Use sed?
sed -e "s/\(.*\)/'\1'/"
Or, as commented below, if the directories might contain apostrophes (nightmare if they do) use this alternate
sed -e "s/'/'\\\\''/g;s/\(.*\)/'\1'/"
Using sed:
sed -i "s/^.*$/'&'/g" filename
You can use sed(1) to insert single quotes at the beginning and end of each line in a file as so:
sed -i~ -e "s/^/'/;s/$/'/" the_file
I prefer awk (it's faster than bash and very easy to extend):
awk '{print "\'" $0 "\'"}'
very simple logic, you just need to echo the quotes in front and behind.
while read -r line
do
echo "'$line'"
# do something
done < "file"
Using sd, to surround with ' the command looks like:
sd '(.*)' \''$1'\'
to surround with " the command looks like:
sd '(.*)' '"$1"'
Hopefully you got the idea.

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