I have a txt file with a line I want to comment, I am using sed
comment out
sed -i 's/line1/#line1/' myfile.ini
uncomment out
sed -i 's/#line1/line1/' myfile.ini
this works but the problem is that sometimes I run this twice by mistake, and I end up with a line like
##line1
so when I run the uncomment command, the line is now
#line1
is there an alternative to toggle the comment? this is inside a bash script so I am happy to add a few lines if necessary.
thanks
You can use this sed command:
sed -i 's/^[[:blank:]]*line1/#&/' myfile.ini
Here matching pattern is ^[[:blank:]]*line1 which means match start of line followed by 0 or more whitespace characters before matching line1. And replacement is #& to place # before matched string.
Similarly for uncommenting use:
sed -Ei 's/^#([[:blank:]]*line1)/\1/' myfile.ini
Which matches # at line start followed by 0 or more whitespaces before matching line1. It capture part after # in capture group #1 and uses back-reference \1 in replacement to remove just the # part.
Building Upon #Anubhava's Answer,
You can combine the two into a One-Liner to Toggle comments with:
sed -Ei 's/^[[:blank:]]*line1/#&/;t;s/^#([[:blank:]]*line1)/\1/' myfile.ini
For MacOS/OSX and Other BSD Systems, You can do:
sed -Ei'' 's/^[[:blank:]]*line1/#&/;t;s/^#([[:blank:]]*line1)/\1/' myfile.ini
This is a simple "if-else" statement in sed.
More About Sed Branching & Flow Control Here
I have this command to run git log and refresh a list of file:
sed -E 's|(.*): .*|echo \1: $(git log -1 --pretty="format:%ct" \1)|e' app/config/file.yml
My problem is this command refresh every line in file.yml but i have a prefix which i don't want to refresh. The prefix is web/compile/*
I tried to do with this but unfortunately delete eveything whitout /web/compile prefix.
sed -i.bkp '/web\/compiled\/*/!e' -E 's|(.*): .*|echo \1: $(git log -1 --pretty="format:%ct" \1)|e' app/config/file.yml
First of all, you should know that using sed to modify a yaml file is risky. (I saw you retain the leading stuff till the last : to avoid interfering the indentations, but it is not safe )
using sed, you can match a pattern by /pattern/{action}, here you just fill the pattern part with your "prefix" path. However, double-check your "prefix", if there are leading spaces(indent), you may want to have \s*/web/com....
similar to your s|pat|rep_or_cmd|e, you can use another separator for the pattern matching, which we talked about in the last item if your pattern contains slash. so \#^\s*/web/compile# will be easier to read
come to solution. You have two different ways to do what you want:
sed '\#^\s*/web/compile#n; s|your s cmd....|' file
OR
sed '\#^\s*/web/compile#!s|your s cmd....|' file
Note
In your question, the prefix you wrote sometimes web/compile sometimes /web/compile, you should write the right one in the sed command and test.
I have a file where I only need numbers [0-9]. I have this command sed 's/[^0-9]*//g' which deletes anything that's not [0-9] but I need to only delete things left of a ","
I have this now, but it isn't working how I'd think it should...
sed -ri "s/[^0-9]+\,/,/g"
As I said in the comment above, I don't understand why 's/[^0-9].\(.*,\)/\1/g' doesn't work, but there are alternatives.
We can use t (test) to do what I expected g to do:
sed -e:a -e 's/[^0-9].\(.*,\)/\1/;ta'
Or use the hold space (overkill, but it works):
sed 'h;s/.*,/,/;x;s/,.*//;s/[^0-9].//g;G;s/\n//'
I have a lot of files that end in the classical ^M, an artifact from my Windows times. As this is all source code, git actually thinks those files changed, so I want to remove those nasty lines once and for all.
Here is what I created:
sed -i 's/^M//g' file
But that does not work. Of course I did not type a literal ^M but rather ^V^M (ctrl V, ctrl M). In vim it works (:%s/s/^M//g) and if I modify it like this:
sed -i 's/^M/a/g' file
It also works, i.e. it ends every line with an 'a'. It also works to do this:
sed -i 's/random_string//g' file
Where random_string exists in the file. So I can replace ^M by any character and I can remove lines but I cannot remove ^M. Why?
Note: It is important that it is just removed, no replacing by another invisible char or something. I would also like to avoid double execution and adding an arbitrary string and removing it afterwards. I want to understand why this fails (but it does not report an error).
That character is matched with \r by sed. Use:
sed -e "s/\r//g" input-file
For my case, I had to do
sed -e "s/\r/\n/g" filename.csv
After that wc -l filename Showed correct output instead of 0 lines.
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