I'm using sed to replace some strings in some of my files. I'm trying to match a string like "namespace Foo\BarBundle\Tests\blah\blah" with this pattern:
^\\(namespace\|use\\)\s\*Foo\BarBundle\Tests\\(.\*\\)$
But it's not working. The Complete command goes as follows:
sed -i -e "s/$pattern/\1 Tests\\Foo\BarBundle\2/g" <file_name>
Where $pattern is the pattern stated above. (which is the output from echo $pattern).
I've ran it on multiple files to no avail. Is there something wrong with the first pattern?
Use 3 backslashes \\\ to specify a regular backsplash \:
pattern="^\(namespace\|use\)\s*Foo\\\BarBundle\\\Tests\(.*\)$"
sed -e "s/$pattern/\1 Tests\\\Foo\\\BarBundle\2/g" <file_name>
The first two \\ become one in the shell which then escape the third one \ in sed
You have to use 4 backslashes if you want to match a single backslash - both in standard input and in the script.
Related
I have file (db-chk.txt) which has multiple rows which start with single quote and I would like to search for this pattern using bash "sed" and remove all those lines which start with single quote (').
Tried few option, but they don't work
$ sed '/^'-/d' db-check.txt -- This one don't work
$ sed '/^\'-/d' db-check.txt
e.g. Sample data from db-check.txt which i want to get these lines removed.
---[BLOCKED/-SESSION]--
----[SESSION/-COUNT]---
In case you don't have any parameter expansion in your sed command, you can use double quote (as mentioned in comment):
sed -i "/'^-/d" db-check.txt
If you don't want parameter expansion, use single quote:
sed -i '/^\x27-/d' db-check.txt
\x27 is the hex code for the '
Is there a way in (Gnu) sed to replace all characters in a matching part of a string? For example I might have a list of file paths with several (arbitrary number of) paths in each line, e.g.:
/a/b/c/d/e /f/g/XXX/h/i /j/k/l/m
/n/o/p /q/r/s/t/u /v/x/x/y
/z/XXX/a/b /c/d/e/f
I would like to replace all the slashes in paths containing XXX keping all the others untouched, e.g.:
/a/b/c/d/e #f#g#XXX#h#i /j/k/l/m
/n/o/p /q/r/s/t/u /v/x/x/y
#z#XXX#a#b /c/d/e/f
Unfortunately I cannot come up with a solution. Maybe it's even impossible with sed. But I'm curious if somebody find a way to solve the problem.
We can replace any / preceding XXX with no intervening spaces like this:
# Using extended regex syntax
s!/([^ ]*XXX)!#\1!
It's a very similar substitution for those that follow XXX.
Putting them together in a loop makes this program:
#!/bin/sed -rf
:loop
s!/([^ ]*XXX)!#\1!
s!(XXX[^ ]*)/!\1#!
tloop
Output:
/a/b/c/d/e #f#g#XXX#h#i /j/k/l/m
/n/o/p /q/r/s/t/u /v/x/x/y
#z#XXX#a#b /c/d/e/f
That said, it might be simpler to use a pipeline, to break the file paths into individual lines and then reassemble them after the substitution:
sed -e 's/ *$//;s/ */&\n/g' \
| sed -e '/XXX/y,/,#,' \
| sed -e ':a;/ $/{N;s/\n//;ba}'
I need to comment out a line in a crontab file through a script, so it contains directories, spaces and symbols. This specific line is stored in a variable and I am starting to get mixed up on how to escape the variable. Since the line changes on a regular basis I dont want any escaping in there. I don't want to simply add # in front of it, since I also need to switch it around and replace the line again with the original without the #.
So the goal is to replace $line with #$line (comment) with the possibility to do it the other way around (uncomment).
So I have a variable:
line="* * * hello/this/line & /still/this/line"
This is a line that occurs in a file, file.txt. Wich needs to get comment out.
First try:
sed -i "s/^${line}/#${line}/" file.txt
Second try:
sed -i 's|'${line}'|'"#${line}"'|g' file.txt
choroba's helpful answer shows an effective solution using perl.
sed solution
If you want to use sed, you must use a separate sed command just to escape the $line variable value, because sed has no built-in way to escape strings for use as literals in a regex context:
lineEscaped=$(sed 's/[^^]/[&]/g; s/\^/\\^/g' <<<"$line") # escape $line for use in regex
sed -i "s/^$lineEscaped\$/#&/" file.txt # Note the \$ to escape the end-of-line anchor $
With BSD/macOS sed, use -i '' instead of just -i for in-place updating without backup.
And the reverse (un-commenting):
sed -i "s/^#\($lineEscaped\)\$/\1/" file.txt
See this answer of mine for an explanation of the sed command used for escaping, which should work with any input string.
Also note how variable $lineEscaped is only referenced once, in the regex portion of the s command, whereas the substitution-string portion simply references what the regex matched (which avoids the need to escape the variable again, using different rules):
& in the substitution string represents the entire match, and \1 the first capture group (parenthesized subexpression, \(...\)).
For simplicity, the second sed command uses double quotes in order to embed the value of shell variable $lineEscaped in the sed script, but it is generally preferable to use single-quoted scripts so as to avoid confusion between what the shell interprets up front vs. what sed ends up seeing.
For instance, $ is special to both the shell and sed, and in the above script the end-of-line anchor $ in the sed regex must therefore be escaped as \$ to prevent the shell from interpreting it.
One way to avoid confusion is to selectively splice double-quoted shell-variable references into the otherwise single-quoted script:
sed -i 's/^'"$lineEscaped"'$/#&/' file.txt
awk solution
awk offers literal string matching, which obviates the need for escaping:
awk -v line="$line" '$0 == line { $0 = "#" $0 } 1' file.txt > $$.tmp && mv $$.tmp file.txt
If you have GNU Awk v4.1+, you can use -i inplace for in-place updating.
And the reverse (un-commenting):
awk -v line="#$line" '$0 == line { $0 = substr($0, 2) } 1' file.txt > $$.tmp &&
mv $$.tmp file.txt
Perl has ways to do the quoting/escaping for you:
line=$line perl -i~ -pe '$regex = quotemeta $ENV{line}; s/^$regex/#$ENV{line}/' -- input.txt
I need to modify some Windows paths.
For instance,
D:\usr
to
D:\first\usr
So, I have created a variable.
$path = "first\usr"
then used the following command:
sed -i -e 's!\\usr!${path}/g;' test.txt
However, this ends up with the following:
D:\firstSr
How do I escape \u in sed?
Assuming your path variable was assigned properly (without spaces in the assignment: path='first\usr'), fixing step by step for an input file test.txt with one example path:
$ cat test.txt
D:\usr
Your original command
$ sed 's!\\usr!${path}/g;' test.txt
sed: -e expression #1, char 18: unterminated `s' command
doesn't do much, as you've mixed ! and / as the delimiter.
Fixing delimiters:
$ sed 's!\\usr!${path}!g;' test.txt
D:${path}
Now no interpolation happens at all because of the single quotes. I suspect these are just copy-paste mistakes, as you obviously got some output.
Double quotes:
$ sed "s!\\usr!${path}!g" test.txt
bash: !\\usr!${path}!g: event not found
Now this clashes with history expansion. We could escape the !, or use a different delimiter.
/ as delimiter:
$ sed "s/\\usr/${path}/g" test.txt
D:\firstSr
Now we're where the question actually started. ${path} expands to first\usr, but \u has a special meaning in GNU sed in the replacement string: it uppercases the following character, hence the S.
Even without the special meaning, \u would most likely just expand to u and the backslash would be gone.
Escaping the backslash:
$ path='first\\usr'
$ sed "s/\\usr/${path}/g" test.txt
D:\first\usr
This works.
Depending on which shell you are using, you may be able to use parameter expansion to double \ in your substitution string and prevent the \u interpretation:
path="first\usr"
sed -e "s/\\usr/${path//\\/\\\\}/g" <<< "D:\usr"
The syntax for replacing a pattern with the shell parameter expansion is ${parameter/pattern/string} (one replacement) or ${parameter//pattern/string} (replace all matches).
This substitution is not specified by POSIX, but is available in Bash.
Where it is not available, you may need to filter $path through a process:
path=$(echo "$path" | sed 's/[][\\*.%$]/\\&/g')
(N.B. I have also quoted other sed metacharacters in this filter).
This question already has answers here:
Using different delimiters in sed commands and range addresses
(3 answers)
Closed 1 year ago.
I have a Visual Studio project, which is developed locally. Code files have to be deployed to a remote server. The only problem is the URLs they contain, which are hard-coded.
The project contains URLs such as ?page=one. For the link to be valid on the server, it must be /page/one .
I've decided to replace all URLs in my code files with sed before deployment, but I'm stuck on slashes.
I know this is not a pretty solution, but it's simple and would save me a lot of time. The total number of strings I have to replace is fewer than 10. A total number of files which have to be checked is ~30.
An example describing my situation is below:
The command I'm using:
sed -f replace.txt < a.txt > b.txt
replace.txt which contains all the strings:
s/?page=one&/pageone/g
s/?page=two&/pagetwo/g
s/?page=three&/pagethree/g
a.txt:
?page=one&
?page=two&
?page=three&
Content of b.txt after I run my sed command:
pageone
pagetwo
pagethree
What I want b.txt to contain:
/page/one
/page/two
/page/three
The easiest way would be to use a different delimiter in your search/replace lines, e.g.:
s:?page=one&:pageone:g
You can use any character as a delimiter that's not part of either string. Or, you could escape it with a backslash:
s/\//foo/
Which would replace / with foo. You'd want to use the escaped backslash in cases where you don't know what characters might occur in the replacement strings (if they are shell variables, for example).
The s command can use any character as a delimiter; whatever character comes after the s is used. I was brought up to use a #. Like so:
s#?page=one&#/page/one#g
A very useful but lesser-known fact about sed is that the familiar s/foo/bar/ command can use any punctuation, not only slashes. A common alternative is s#foo#bar#, from which it becomes obvious how to solve your problem.
add \ before special characters:
s/\?page=one&/page\/one\//g
etc.
In a system I am developing, the string to be replaced by sed is input text from a user which is stored in a variable and passed to sed.
As noted earlier on this post, if the string contained within the sed command block contains the actual delimiter used by sed - then sed terminates on syntax error. Consider the following example:
This works:
$ VALUE=12345
$ echo "MyVar=%DEF_VALUE%" | sed -e s/%DEF_VALUE%/${VALUE}/g
MyVar=12345
This breaks:
$ VALUE=12345/6
$ echo "MyVar=%DEF_VALUE%" | sed -e s/%DEF_VALUE%/${VALUE}/g
sed: -e expression #1, char 21: unknown option to `s'
Replacing the default delimiter is not a robust solution in my case as I did not want to limit the user from entering specific characters used by sed as the delimiter (e.g. "/").
However, escaping any occurrences of the delimiter in the input string would solve the problem.
Consider the below solution of systematically escaping the delimiter character in the input string before having it parsed by sed.
Such escaping can be implemented as a replacement using sed itself, this replacement is safe even if the input string contains the delimiter - this is since the input string is not part of the sed command block:
$ VALUE=$(echo ${VALUE} | sed -e "s#/#\\\/#g")
$ echo "MyVar=%DEF_VALUE%" | sed -e s/%DEF_VALUE%/${VALUE}/g
MyVar=12345/6
I have converted this to a function to be used by various scripts:
escapeForwardSlashes() {
# Validate parameters
if [ -z "$1" ]
then
echo -e "Error - no parameter specified!"
return 1
fi
# Perform replacement
echo ${1} | sed -e "s#/#\\\/#g"
return 0
}
this line should work for your 3 examples:
sed -r 's#\?(page)=([^&]*)&#/\1/\2#g' a.txt
I used -r to save some escaping .
the line should be generic for your one, two three case. you don't have to do the sub 3 times
test with your example (a.txt):
kent$ echo "?page=one&
?page=two&
?page=three&"|sed -r 's#\?(page)=([^&]*)&#/\1/\2#g'
/page/one
/page/two
/page/three
replace.txt should be
s/?page=/\/page\//g
s/&//g
please see this article
http://netjunky.net/sed-replace-path-with-slash-separators/
Just using | instead of /
Great answer from Anonymous. \ solved my problem when I tried to escape quotes in HTML strings.
So if you use sed to return some HTML templates (on a server), use double backslash instead of single:
var htmlTemplate = "<div style=\\"color:green;\\"></div>";
A simplier alternative is using AWK as on this answer:
awk '$0="prefix"$0' file > new_file
You may use an alternative regex delimiter as a search pattern by backs lashing it:
sed '\,{some_path},d'
For the s command:
sed 's,{some_path},{other_path},'