hi trying to replace the following string with a long one :
@x@
with string that I got from the command line:
read test
sed -i --backup 's/@x@/'${test}'/g' file.json README.md
but it is working only for 1 word, it is not working if there is space between word . even between quotes
sed: 1: "s/@x@/string test string: unterminated substitute in regular expression
if case you run it on MacOS and struggling with "unterminated substitute in regular expression", there is an easier explanation for this:
MacOS has slightly other version of sed than usually is on linux. -i requires a parameter. If you have none, just add "" after -i
sed -i "" --backup 's/@x@/'${test}'/g' file.json README.md
or for example if you just have to delete dome line, this works on linux, but brings “invalid command code” on MacOS
sed -i 39d filenamehere.log
and this works on MacOS
sed -i "" 39d filenamehere.log
The problem originates from the way you are using the single-quotes. Currently you are terminating your input behind the 2. single-quote. See the Error message, it makes you aware of the fact that it is missing something.
If you have a file with the following content:
foo @x@ foo
Than you can replace the content e.g. with the following command:
sed 's/@x@/bar foo bar/' foo.txt > foo2.txt
And get:
foo bar foo bar foo
If you need to pass in a variable the comment from Gordon Davisson shows you the right way.
By the way, if you want to use the inplace option, on my linux you would need to use the command like this:
sed -i.old "s/@x@/${test}/" foo.txt
But I think this might depends on your enviroment (mac?).
sed doesn't understand strings where a string is a series of literal characters. It replaces a regexp (not a string) with a backreference-enabled "string" (also not a string) all within a set of delimiters (which ALSO require careful handling in both the regexp and the replacement). See Is it possible to escape regex metacharacters reliably with sed for more info.
To replace a string with another string the simplest approach is to just use a tool that understands strings such as awk:
$ cat file
before stuff
foo @x@ bar
after stuff
$ cat tst.awk
BEGIN {
old = ARGV[1]
new = ARGV[2]
ARGV[1] = ARGV[2] = ""
}
s = index($0,old) { $0 = substr($0,1,s-1) new substr($0,s+length(old)) }
{ print }
$ test='a/\t/&"b'
$ awk -f tst.awk '@x@' "$test" file
before stuff
foo a/\t/&"b bar
after stuff
The above will work no matter what characters test contains, even newlines:
$ test='contains a
newline'
$ awk -f tst.awk '@x@' "$test" file
before stuff
foo contains a
newline bar
after stuff
