How to add quote at the end of line by SED - sed

sed -i 's/$/\'/g'
sed -i "s/$/\'/g"
How to escape both $ and ' by 1 command?

This might work for you (GNU sed):
sed 's/$/'\''/' file
Adds a single quote to the end of a line.
sed 's/\$/'\''/' file
Replaces a $ by a single quote.
sed 's/\$$/'\''/' file
Replaces a $ at the end of line by a single quote.
N.B. Surrounding sed commands by double quotes is fine for some interpolation but may return unexpected results.

Use octal values
sed 's/$/\o47/'
Care to use backslash + letter o minus + octal number 1 to 3 digit

Just don't use single quotes to start the sed script?
sed "s/$/'/"
The /g at the end means to apply everywhere it's found on each stream (line) - you don't need this since $ is a special character indicating end of stream.

To add a quote at the end of a line use
sed -i "s/$/'/g" file
sed -i 's/$/'"'"'/g' file
See proof.
If there are already single quotes, and you want to make sure there is single occurrence at the end of string use
sed -i "s/'*$/'/g" file
sed -i 's/'"'*"'$/'"'"'/g' file
See this proof.
To escape $ and ' chars use
sed -i "s/[\$']/\\\\&/g" file
See proof
[\$'] - matches $ (escaped as in double quotes it can be treated as a variable interpolation char) or '
\\\\& - a backslash (need 4, that is literal 2 backslashes, it is special in the replacement), and & is the whole match.

Related

sed replace with backslash, double quote, single quote

Can you give the sed command that will find \" and replace with \\' in a file.
For example line:
LOG_FN=\"file_name\"
will become
LOG_FN=\\'file_name\\'
By using this template:
sed -i 's/old-text/new-text/g' input.txt
I tried following sed commands:
sed -i 's/\\\"/\\\\\'/g' input.txt
sed -i "s/\\\"/\\\\'/g" input.txt
Unfortunately they fail because what I am looking for is a string substitution for \" while commands I tried change individual " characters.
You can't escape a single quote inside single quotes. Your second attempt needs more backslashes: Remember, inside double quotes, the shell processes one layer of backslashes, so you have to double each backslash which should make it through to sed.
sed "s/\\\\\"/\\\\\\\\'/g" input.txt
After the shell has processed the double-quoted string, the script which ends up being executed is
s/\\"/\\\\'/g
where the first pair of backslashes produce a literal backslash in the matching regex, and each pair of backslashes in the replacement produce one literal backslash in the output.
Demo: https://ideone.com/XqfwbV

sed to remove lines starting with single quotes

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 '

How to replace \n by space using sed command?

I have to collect a select query data to a CSV file. I want to use a sed command to replace \n from the data by a space.
I'm using this:
query | sed "s/\n/ /g" > file.csv .......
But it is not working. Only \ is getting removed, while it should also remove n and add a space. Please suggest something.
You want to replace newline with space, not necessarily using sed.
Use tr:
tr '\n' ' '
\n is special to sed: it stands for the newline character. To replace a literal \n, you have to escape the backslash:
sed 's/\\n/ /g'
Notice that I've used single quotes. If you use double quotes, the backslash has a special meaning if followed by any of $, `, ", \, or newline, i.e., "\n" is still \n, but "\\n" would become \n.
Since we want sed to see \\n, we'd have to use one of these:
sed "s/\\\n/ /g" – the first \\ becomes \, and \n doesn't change, resulting in \\n
sed "s/\\\\n/ /g" – both pairs of \\ are reduced to \ and sed gets \\n as well
but single quotes are much simpler:
$ sed 's/\\n/ /g' <<< 'my\nname\nis\nrohinee'
my name is rohinee
From comments on the question, it became apparent that sed had nothing to do with removing the backslashes; the OP tried
echo my\nname\nis | sed 's/\n/ /g'
but the backslashes are removed by the shell:
$ echo my\nname\nis
mynnamenis
so even if the correct \\n were used, sed wouldn't find any matches. The correct way is
$ echo 'my\nname\nis' | sed 's/\\n/ /g'
my name is

Delete line if string between the 4th and 5th delimiter is empty

"text";"text";"text";"text";;"text";"text"
If after the 4th delimiter the next one is following the line should be deleted.
Actually i'm doing that by using sed
sed -n '/;;/!p' input.txt
Is this a reliable solution?
Thanks for help.
Securing a bit potential escaped double quote and internal ";" (thanks #SLePort for remark)
sed -e 'h;s/\\"//g' -e ':c' -e 's/^\(\("[^"]*";\)*"[^"]*\);/\1/;t c' -e '/^\([^;]*;\)\{4\};/d;h'
sed -r '/^([^;]+;){4}\s*;/d' input.txt
awk -F';' '$5' input.txt
To remove lines containing ; after fourth delimiter:
sed '/^\("*[^"]*"*;\)\{4\};/d' input.txt
This might work for you (GNU sed):
sed -r '/^("(\\.|[^"])*";){4};/d' file
If the fourth grouping of double quotes followed by semi colon, where the characters within the grouping are either a pair of a quote and any other character or not a double quote, is followed by a further semi colon, then delete the line.
A more efficient regexp would be:
sed -r '/^("[^"\\]*(\\.[^"\\]*)*";){4};/d' file
This uses the pattern normal*(abnormal normal*)*

Substitute with backslash in sed

I want to replace word with \word{sth} with sed.
I type in
sed -i s#word#\\word{sth}
but i am getting is word{sth} instead of \word{sth}
I tried with 1 slash also in the command
you should add four backslashes.
you need two to escape the backslash by the terminal, and two to escape it for sed. 2*2=4.
$ echo word|sed s#word#\\\\word{sth}#gi
\word{sth}
Consider enclosing sed expression with single-quotes '
sed -i 's#word#\\word{sth}#' file