Please see these simple commands:
$ echo $tmp
UY\U[_
$ echo "a" | sed "s|a|${tmp}|g"
UY[_
The \U is eaten. Other backslashes won't survive either.
How can I make the above command work as expected?
If it's only backslash that is "eaten" by sed and escaping just that is enough, then try:
echo "a" | sed "s|a|${tmp//\\/\\\\}|g"
Confusing enough for you? \\ represents a single \ since it needs to be escaped in the shell too.
The inital // is similar to the g modifier in s/foo/bar/g, if you only want the first occurring pattern to be replaced, skip it.
The docs about ${parameter/pattern/string} is available here: http://www.gnu.org/s/bash/manual/bash.html#Shell-Parameter-Expansion
Edit: Depending on what you want to do, you might be better of not using sed for this actually.
$ tmp="UY\U[_"
$ in="a"
$ echo ${in//a/$tmp}
UY\U[_
You could reparse $tmp itself through sed
echo "a" | sed "s|a|$(echo ${tmp} | sed 's|\\|\\\\|g')|g"
Related
If I run these commands from a script:
#my.sh
PWD=bla
sed 's/xxx/'$PWD'/'
...
$ ./my.sh
xxx
bla
it is fine.
But, if I run:
#my.sh
sed 's/xxx/'$PWD'/'
...
$ ./my.sh
$ sed: -e expression #1, char 8: Unknown option to `s'
I read in tutorials that to substitute environment variables from shell you need to stop, and 'out quote' the $varname part so that it is not substituted directly, which is what I did, and which works only if the variable is defined immediately before.
How can I get sed to recognize a $var as an environment variable as it is defined in the shell?
Your two examples look identical, which makes problems hard to diagnose. Potential problems:
You may need double quotes, as in sed 's/xxx/'"$PWD"'/'
$PWD may contain a slash, in which case you need to find a character not contained in $PWD to use as a delimiter.
To nail both issues at once, perhaps
sed 's#xxx#'"$PWD"'#'
In addition to Norman Ramsey's answer, I'd like to add that you can double-quote the entire string (which may make the statement more readable and less error prone).
So if you want to search for 'foo' and replace it with the content of $BAR, you can enclose the sed command in double-quotes.
sed 's/foo/$BAR/g'
sed "s/foo/$BAR/g"
In the first, $BAR will not expand correctly while in the second $BAR will expand correctly.
Another easy alternative:
Since $PWD will usually contain a slash /, use | instead of / for the sed statement:
sed -e "s|xxx|$PWD|"
You can use other characters besides "/" in substitution:
sed "s#$1#$2#g" -i FILE
一. bad way: change delimiter
sed 's/xxx/'"$PWD"'/'
sed 's:xxx:'"$PWD"':'
sed 's#xxx#'"$PWD"'#'
maybe those not the final answer,
you can not known what character will occur in $PWD, / : OR #.
if delimiter char in $PWD, they will break the expression
the good way is replace(escape) the special character in $PWD.
二. good way: escape delimiter
for example:
try to replace URL as $url (has : / in content)
x.com:80/aa/bb/aa.js
in string $tmp
URL
A. use / as delimiter
escape / as \/ in var (before use in sed expression)
## step 1: try escape
echo ${url//\//\\/}
x.com:80\/aa\/bb\/aa.js #escape fine
echo ${url//\//\/}
x.com:80/aa/bb/aa.js #escape not success
echo "${url//\//\/}"
x.com:80\/aa\/bb\/aa.js #escape fine, notice `"`
## step 2: do sed
echo $tmp | sed "s/URL/${url//\//\\/}/"
URL
echo $tmp | sed "s/URL/${url//\//\/}/"
URL
OR
B. use : as delimiter (more readable than /)
escape : as \: in var (before use in sed expression)
## step 1: try escape
echo ${url//:/\:}
x.com:80/aa/bb/aa.js #escape not success
echo "${url//:/\:}"
x.com\:80/aa/bb/aa.js #escape fine, notice `"`
## step 2: do sed
echo $tmp | sed "s:URL:${url//:/\:}:g"
x.com:80/aa/bb/aa.js
With your question edit, I see your problem. Let's say the current directory is /home/yourname ... in this case, your command below:
sed 's/xxx/'$PWD'/'
will be expanded to
sed `s/xxx//home/yourname//
which is not valid. You need to put a \ character in front of each / in your $PWD if you want to do this.
Actually, the simplest thing (in GNU sed, at least) is to use a different separator for the sed substitution (s) command. So, instead of s/pattern/'$mypath'/ being expanded to s/pattern//my/path/, which will of course confuse the s command, use s!pattern!'$mypath'!, which will be expanded to s!pattern!/my/path!. I’ve used the bang (!) character (or use anything you like) which avoids the usual, but-by-no-means-your-only-choice forward slash as the separator.
Dealing with VARIABLES within sed
[root#gislab00207 ldom]# echo domainname: None > /tmp/1.txt
[root#gislab00207 ldom]# cat /tmp/1.txt
domainname: None
[root#gislab00207 ldom]# echo ${DOMAIN_NAME}
dcsw-79-98vm.us.oracle.com
[root#gislab00207 ldom]# cat /tmp/1.txt | sed -e 's/domainname: None/domainname: ${DOMAIN_NAME}/g'
--- Below is the result -- very funny.
domainname: ${DOMAIN_NAME}
--- You need to single quote your variable like this ...
[root#gislab00207 ldom]# cat /tmp/1.txt | sed -e 's/domainname: None/domainname: '${DOMAIN_NAME}'/g'
--- The right result is below
domainname: dcsw-79-98vm.us.oracle.com
VAR=8675309
echo "abcde:jhdfj$jhbsfiy/.hghi$jh:12345:dgve::" |\
sed 's/:[0-9]*:/:'$VAR':/1'
where VAR contains what you want to replace the field with
I had similar problem, I had a list and I have to build a SQL script based on template (that contained #INPUT# as element to replace):
for i in LIST
do
awk "sub(/\#INPUT\#/,\"${i}\");" template.sql >> output
done
If your replacement string may contain other sed control characters, then a two-step substitution (first escaping the replacement string) may be what you want:
PWD='/a\1&b$_' # these are problematic for sed
PWD_ESC=$(printf '%s\n' "$PWD" | sed -e 's/[\/&]/\\&/g')
echo 'xxx' | sed "s/xxx/$PWD_ESC/" # now this works as expected
for me to replace some text against the value of an environment variable in a file with sed works only with quota as the following:
sed -i 's/original_value/'"$MY_ENVIRNONMENT_VARIABLE"'/g' myfile.txt
BUT when the value of MY_ENVIRONMENT_VARIABLE contains a URL (ie https://andreas.gr) then the above was not working.
THEN use different delimiter:
sed -i "s|original_value|$MY_ENVIRNONMENT_VARIABLE|g" myfile.txt
Cannot seem to find an answer to this one online...
I have a string variable (externally sourced) with new lines "\n" encoded as strings.
I want to replace those strings with actual new line carriage returns. The code below can achieve this...
echo $EXT_DESCR | sed 's/\\n/\n/g'
But when I try to store the result of this into it's own variable, it converts them back to strings
NEW_DESCR=`echo $EXT_DESCR | sed 's/\\n/\n/g'`
How can this be achieved, or what I'm I doing wrong?
Here's my code I've been testing to try get the right results
EXT_DESCR="This is a text\nWith a new line"
echo $EXT_DESCR | sed 's/\\n/\n/g'
NEW_DESCR=`echo $EXT_DESCR | sed 's/\\n/\n/g'`
echo ""
echo "$NEW_DESCR"
No need for sed, using parameter expansion:
$ foo='1\n2\n3'; echo "${foo//'\n'/$'\n'}"
1
2
3
With bash 4.4 or newer, you can use the E operator in ${parameter#operator}:
$ foo='1\n2\n3'; echo "${foo#E}"
1
2
3
Other answers contain alternative solutions. (I especially like the parameter expansion one.)
Here's what's wrong with your attempt:
In
echo $EXT_DESCR | sed 's/\\n/\n/g'
the sed command is in single quotes, so sed gets s/\\n/\n/g as is.
In
NEW_DESCR=`echo $EXT_DESCR | sed 's/\\n/\n/g'`
the whole command is in backticks, so a round of backslash processing is applied. That leads to sed getting the code s/\n/\n/g, which does nothing.
A possible fix for this code:
NEW_DESCR=`echo $EXT_DESCR | sed 's/\\\\n/\\n/g'`
By doubling up the backslashes, we end up with the right command in sed.
Or (easier):
NEW_DESCR=$(echo $EXT_DESCR | sed 's/\\n/\n/g')
Instead of backticks use $( ), which has less esoteric escaping rules.
Note: Don't use ALL_UPPERCASE for your shell variables. UPPERCASE is (informally) reserved for system variables such as HOME and special built-in variables such as IFS or RANDOM.
Depending on what exactly you need it for:
echo -e $EXT_DESCR
might be all you need.
From echo man page:
-e
enable interpretation of backslash escapes
This printf would do the job by interpreting all escaped constructs:
printf -v NEW_DESCR "%b" "$EXT_DESCR"
-v option will store output in a variable so no need to use command substitution here.
Problem with your approach is use of old back-ticks. You could do:
NEW_DESCR=$(echo "$EXT_DESCR" | sed 's/\\n/\n/g')
Assuming you're using gnu sed as BSD sed won't work with this approach.
I have a shell script that accepts a parameter that is comma delimited,
-s 1234,1244,1567
That is passed to a curl PUT json field. Json needs the values in a "1234","1244","1567" format.
Currently, I am passing the parameter with the quotes already in it:
-s "\"1234\",\"1244\",\"1567\"", which works, but the users are complaining that its too much typing and hard to do. So I'd like to just take a comma delimited list like I had at the top and programmatically stick the quotes in.
Basically, I want a parameter to be passed in as 1234,2345 and end up as a variable that is "1234","2345"
I've come to read that easiest approach here is to use sed, but I'm really not familiar with it and all of my efforts are failing.
You can do this in BASH:
$> arg='1234,1244,1567'
$> echo "\"${arg//,/\",\"}\""
"1234","1244","1567"
awk to the rescue!
$ awk -F, -v OFS='","' -v q='"' '{$1=$1; print q $0 q}' <<< "1234,1244,1567"
"1234","1244","1567"
or shorter with sed
$ sed -r 's/[^,]+/"&"/g' <<< "1234,1244,1567"
"1234","1244","1567"
translating this back to awk
$ awk '{print gensub(/([^,]+)/,"\"\\1\"","g")}' <<< "1234,1244,1567"
"1234","1244","1567"
you can use this:
echo QV=$(echo 1234,2345,56788 | sed -e 's/^/"/' -e 's/$/"/' -e 's/,/","/g')
result:
echo $QV
"1234","2345","56788"
just add double quotes at start, end, and replace commas with quote/comma/quote globally.
easy to do with sed
$ echo '1234,1244,1567' | sed 's/[0-9]*/"\0"/g'
"1234","1244","1567"
[0-9]* zero more consecutive digits, since * is greedy it will try to match as many as possible
"\0" double quote the matched pattern, entire match is by default saved in \0
g global flag, to replace all such patterns
In case, \0 isn't recognized in some sed versions, use & instead:
$ echo '1234,1244,1567' | sed 's/[0-9]*/"&"/g'
"1234","1244","1567"
Similar solution with perl
$ echo '1234,1244,1567' | perl -pe 's/\d+/"$&"/g'
"1234","1244","1567"
Note: Using * instead of + with perl will give
$ echo '1234,1244,1567' | perl -pe 's/\d*/"$&"/g'
"1234""","1244""","1567"""
""$
I think this difference between sed and perl is similar to this question: GNU sed, ^ and $ with | when first/last character matches
Using sed:
$ echo 1234,1244,1567 | sed 's/\([0-9]\+\)/\"\1\"/g'
"1234","1244","1567"
ie. replace all strings of numbers with the same strings of numbers quoted using backreferencing (\1).
I work on shell script and I want to remove all space characters in a string.
On another question I saw a sed command for replacing and tried to use it with sending null character in it:
echo \0 | sed "s/ /${text}/"
But it did not work.
Any other way to do this?
This deletes all space characters in the input:
echo some text with spaces | tr -d ' '
Another way using sed:
echo some text with spaces | sed -e 's/ //g'
But... In your example there are no spaces, and it looks like you want to replace spaces with the content of the variable $text... So not 100% sure this is what you're looking for. So if not, then please clarify.
This was my use case:
Multiple key values that should go on a single string. I'd like to split the string to make them easier to read.
SPLIT=" \
KEY_1=$VALUE_1, \
KEY_2=$VALUE_2, \
KEY_3=$VALUE_3 \
"
JOINED="$(echo "$SPLIT" | sed "s/ //g")" # REMOVE SPACES
echo $JOINED
This question already has answers here:
Replace a word with multiple lines using sed?
(11 answers)
Closed 4 years ago.
I am trying to replace a word with a text which spans multiple lines. I know that I can simply use the newline character \n to solve this problem, but I want to keep the string "clean" of any unwanted formatting.
The below example obviously does not work:
read -r -d '' TEST <<EOI
a
b
c
EOI
sed -e "s/TOREPLACE/${TEST}/" file.txt
Any ideas of how to achieve this WITHOUT modifying the part which starts with read and ends with EOI?
Given that you're using Bash, you can use it to substitute \n for the newlines:
sed -e "s/TOREPLACE/${TEST//$'\n'/\\n}/" file.txt
To be properly robust, you'll want to escape /, & and \, too:
TEST="${TEST//\\/\\\\}"
TEST="${TEST//\//\\/}"
TEST="${TEST//&/\\&}"
TEST="${TEST//$'\n'/\\n}"
sed -e "s/TOREPLACE/$TEST/" file.txt
If your match is for a whole line and you're using GNU sed, then it might be easier to use its r command instead:
sed -e $'/TOREPLACE/{;z;r/dev/stdin\n}' file.txt <<<"$TEST"
You can just write the script as follows:
sed -e 's/TOREPLACE/a\
b\
c\
/g' file.txt
A little cryptic, but it works. Note also that the file won't be modified in place unless you use the -i option.
tricky... but my solution would be :-
read -r -d '' TEST <<EOI
a
b
c
EOI
sed -e "s/TOREPLACE/`echo "$TEST"|awk '{printf("%s\\\\n", $0);}'|sed -e 's/\\\n$//'`/g" file.txt
Important:
Make sure you use the correct backticks, single quotes, double quotes and spaces
else it will not work.
An interesting question..
This may get you closer to a solution for your use case.
read -r -d '' TEST <<EOI
a\\
b\\
c
EOI
echo TOREPLACE | sed -e "s/TOREPLACE/${TEST}/"
a
b
c
I hope this helps.