I want to remove "^#^#^#^#^#^#^#^#^#" from my textfile. I tried the following, but it did not work:
sed -i 's/\\^#//g' myfile.txt
sed is not generally robust against null characters. But Perl is, and tr:
tr -d '\000' <myfile.txt >newfile.txt
Some sed variants will be able to handle null bytes with the notation which works in Perl:
perl -i -pe 's/\x00//g' myfile.txt
The -i option says to replace the original file, like some sed variants also allow you to.
^# is one of the ways how to display the null byte. sed (at least the GNU one) represents it as \x00:
sed 's/\x00//g'
Related
I'm trying to replace the text using the sed, but it's showing some error. Not getting where I'm getting wrong.
sed -i 's/process.env.REDIRECT_URI/http:\/\/test-domain.apps.io/\callback/g' input.txt
Have this :
process.env.REDIRECT_URI
Replace this with :
http://test-domain.apps.io
Try:
sed -i 's/process.env.REDIRECT_URI/http:\/\/test-domain.apps.io/g' input.txt
Notes:
The original command has a spurious string /\callback. All that was needed to make the code work was to remove it.
. is a wildcard. If you want to be sure that you are matching periods, they should be escaped:
sed -i 's/process\.env\.REDIRECT_URI/http:\/\/test-domain.apps.io/g' input.txt
Sometimes, its clearer if one doesn't have to escape /. One can use a separator of one's choice. For example, use #:
sed -i 's#process\.env\.REDIRECT_URI#http://test-domain.apps.io#g' input.txt
If you did want /callback in the output, use:
sed -i 's/process\.env\.REDIRECT_URI/http:\/\/test-domain.apps.io\/callback/g' input.txt
or:
sed -i 's#process\.env\.REDIRECT_URI#http://test-domain.apps.io/callback#g' input.txt
I stumble upon the command sed -e 's/ /\'$'\n/g'that supposedly takes an input and split all spaces into new lines. Still, I don't quite get how the '$' works in the command. I know that s stands for substitute, / / stands for the blank spac, \n stands for new line and /g is for global replacement, but not sure how \'$' fits in the picture. Anybody who can shed some light here will be much appreciated.
Basically it's meant for platform portability. With GNU sed it would be just
sed -e 's/ /\n/g'
because GNU sed is able to interpret \n as new line.
However, other versions of sed, like the BSD version (that comes with MacOS) do not interprete \n as newline.
That's why the command is build out of two parts
sed -e 's/ /\' part2: $'\n/g'
The $'\n/g' is an ANSI C string parsed by the shell before executing sed. Escape sequences like \n will get expanded in such strings. Doing so, the author of the command passed a literal new line (0xa) to the sed command rather than passing the escape sequence \n. (0x5c 0x6e).
One more thing, since the newline (0xa) is a command separator in sed, it needs to get escaped. That's why the \ at the end of the first part.
Alternatively you could just use a multiline version:
sed -e 's/ /\
/g'
Btw, I would have written the command like
sed -e 's/ /\'$'\n''/g'
meaning just putting the $'\n' into the ANSI C string. Imo that's better to understand.
Am running BASH and UNIX utilities on Windows 7.
Have a file that contains a vertical tab. The binary symbol is 0x0B. The octal symbol is 013. I need to replace the symbol with a blank space.
Have tried this sed approach but it fails:
sed -e 's/'$(echo "octal-value")'/replace-word/g'
Specifically:
sed -e 's/'$(echo "\013")'/ /g'
Update:
Following this advice I use GNU sed and this approach:
sed -i 's:\0x0B: :g' file
but the stubborn vertical tab is still in the file.
What is the correct way to replace a non-printable character with a printable character?
Sed should recognise special characters:
sed -e 's/\x0b/ /g'
In answer to why the -e? If you use more than one sed expression, then each one must be preceded by the -e. So, for example:
echo foo bar bas zer | sed -e 's/zer/oh my/g' -e 's/bas/baz/'
would result in:
foo bar baz oh my
thus performing 2 different sed changes ('scripts) with only a single invocation. See sed man pages for more details.
(the above example is, obviously, contrived. I, however, have seen a sed command in a script with 78 individual -e 'scripts'!)
If you only have one 'script', then the -e is optional, obviously.
sed 's_((checksum|compressed)=\").*(\")_\1\2_' -i filename
I am using this command to replace the checksum and compressed filed with empty? But it didn't change anything?
for example, I want change this line " checksum="XXXXX" with checksum="", and also replace
compressed="XXXX" with compressed=""
What is wrong with my sed command?
It's because sed uses a funny regex dialect by default: you have to escape capturing brackets.
If you want to use "normal" regex that you're familiar with, use the -r flag (if you're on unix, GNU sed) or the -E flag (Mac OS X BSD sed):
sed -r 's_((checksum|compressed)=\").*(\")_\1\3_' -i filename
Additionally, note that you have three sets of capturing brackets in your sed, and I think you want to change the \1\2 to \1\3. (\1 contains checksum=", \2 contains checksum, and \3 contains ").
(For interest, here's how you would do it without the extended-regexp (-r/-E) flag, note that capturing brackets and the OR | are only considered in the regex sense if they are escaped:
sed 's_\(\(checksum\|compressed\)=\"\).*\(\"\)_\1\3_' -i filename
)
This might work for you:
echo 'checksum="XXXXX" compressed="YYYYYYY"' |
sed 's/\(checksum\|compressed\)="[^"]*"/\1=""/g'
checksum="" compressed=""
In sed (without the -r switch), ()|+?{}'s must have a \ prepended to give them the qualities of grouping. alternation, one or more, zero or one and intervals. .[]* work as metacharacters either way.
Try:
sed 's/\(\(checksum\|compressed\)\)="[^"]*"/\1=""/' -i filename
I would like one sed command to accomplish the following:
$ sed s'/:/ /g' <and> sed s'/=/ /g'
That is, I would like to write
sed s'/<something>/ /g'
and have both = and : replaced by space.
sed s'/[:=]/ /g'
Brackets mean "any one of".
One option is also to use sed -e, like this. Although you don't need it in this case, it's however a good option to know about.
sed -e 's/:/ /' -e 's/..../ /' file
Sanjay's answer solves it. Another option that works with only one sed command is to separate each s substitution with a semicolon
sed 's/:/ /g ; s/=/ /g' file
or in separate lines in a script
sed 's/:/ /g
s/=/ /g' file
Those may be handy in other situations.