I am trying to delete a line from a text file that has a matching ID number.
Student id variable: $sid, for example 12345678;
$FILE = student_record
I first tried:
sed -i '/$sid/d' student_record.txt
Which gave me file not found. Next:
sed -i '/$sid/d' $FILE
And I get: sed: 1: "student_record": unterminated substitute in regular expression
sed -i '/12345678/d' $FILE
Same error as above
sed -i '/$sid/ d' student_record.txt
yields:
sed 1: "student_record.txt": bad flag in substitute command: 'x'
If I try without -i,
sed '/$sid/ d' $FILE
It just prints the whole file and doesn't delete any lines.
Advice would be great.
If the file is called student_record as you say for $FILE, you may be making a mistake using student_record.txt which would explain while you get file not found.
For many of the others, if you use single quotes it will not expand variables, so you'll literally be looking for the string "$sid". If you use double quotes it will expand, so try
sed -i "/$sid/d" "$FILE"
assuming you have GNU sed. If you're on something that does not have GNU, you may not have -i or it may require an argument.
Related
I've writted a sed script to replace all ^^ with NULL. It seems though that sed is only catching a pair, but not including the second in that pair as it continues to search.
echo "^^^^" | sed 's/\^\^/\^NULL\^/g'
produces
^NULL^^NULL^
when it should produce
^NULL^NULL^NULL^
Try with a loop to apply your command again to modified pattern space:
echo "^^^^" | sed ':a;s/\^\^/\^NULL\^/;t a;'
To edit a file in place on OSX, try the -i flag and multiline command:
sed -i '' ':a
s/\^\^/\^NULL\^/
t a' file
With GNU sed:
sed -i ':a;s/\^\^/\^NULL\^/;t a;' file
or simply redirect the command to a temporary file before renaming it:
sed ':a;s/\^\^/\^NULL\^/;t a;' file > tmp && mv tmp file
I really like SLePort solution, but since it is not working for you, you can try with (tested on Linux, not Mac):
echo "^^^^" | sed 's/\^\^/\^NULL\^/g; s//\^NULL\^/g'
It is doing the same as the former solution, but explicitly, not looping with tags.
You can omit the pattern in the second command and sed will use the previous pattern.
I have a bash script which checks for a string pattern in file and delete entire line i same file but somehow its not deleting the line and no throwing any error .same command from command prompt deletes from file .
#array has patterns
for k in "${patternarr[#]}
do
sed -i '/$k/d' file.txt
done
sed version is >4
when this loop completes i want all lines matching string pattern in array to be deleted from file.txt
when i run sed -i '/pataern/d file.txt from command prompt then it works fine but not inside bash
Thanks in advance
Here:
sed -i '/$k/d' file.txt
The sed script is singly-quoted, which prevents shell variable expansion. It will (probably) work with
sed -i "/$k/d" file.txt
I say "probably" because what it will do depends on the contents of $k, which is just substituted into the sed code and interpreted as such. If $k contains slashes, it will break. If it comes from an untrustworthy source, you open yourself up to code injection (particularly with GNU sed, which can be made to execute shell commands).
Consider k=^/ s/^/rm -Rf \//e; #.
It is generally a bad idea to substitute shell variables into sed code (or any other code). A better way would be with GNU awk:
awk -i inplace -v pattern="$k" '!($0 ~ pattern)' file.txt
Or to just use grep -v and a temporary file.
first of all, you got an unclosed double quote around ${patternarr[#]} in your for statement.
Then your problem is that you use single quotes in the sed argument, making your shell not evaluate the $k within the quotes:
% declare -a patternarr=(foo bar fu foobar)
% for k in ${patternarr[#]}; do echo sed -i '/$k/d' file.txt; done
sed -i /$k/d file.txt
sed -i /$k/d file.txt
sed -i /$k/d file.txt
sed -i /$k/d file.txt
if you replace them with double quotes, here it goes:
% for k in ${patternarr[#]}; do echo sed -i "/$k/d" file.txt; done
sed -i /foo/d file.txt
sed -i /bar/d file.txt
sed -i /fu/d file.txt
sed -i /foobar/d file.txt
Any time you write a loop in shell just to manipulate text you have the wrong approach. This is probably closer to what you really should be doing (no surrounding loop required):
awk -v ks="${patternarr[#]}" 'BEGIN{gsub(/ /,")|(",ks); ks="("ks")} $0 !~ ks' file.txt
but there may be even better approaches still (e.g. only checking 1 field instead of the whole line, or using word boundaries, or string comparison or....) if you show us some sample input and expected output.
You need to use double quotes to interpolate shell variables inside the sed command, like:
for k in ${patternarr[#]}; do
sed -i "/$k/d" file.txt
done
I'm using sed to replace a character in a file with a variable. This variable is basically reading the contents of a file or a webpage which contains multiple hash-like strings like below, which are randomly generated:
define('AUTH_KEY', 'CVo|BO;Qt1B|+GE}+h2/yU7h=5`/wRV{>%h.b_;s%S8-p|>qpf]|/Vf#`&[g~*:&');
define('SECURE_AUTH_KEY', '{G2-<^jWRd7]2,?]6hhM^*asg.2C.+k=gf33-m+ZK_{Mt|q*<ELF4|gPjyxtTh!)');
define('LOGGED_IN_KEY', 'jSNo9Z;5d]tzZoh-QQ`{M-&~y??$R({:*m`0={67=+mF?L.e+R{;)+4}qCAAHz=C');
define('NONCE_KEY', '19Vt4=%8j/Z-&~ni0S<]9)J^~sy9dh|h9M_RX2#K0]F9+.v+[BP1d&B&}-FTKIJ,');
define('AUTH_SALT', 'jr7f?T|#Cbo]XVAo}N^ilkvD>dC-rr]5{al64|?_Hz }JG$yEi:_aU )Olp YAD+');
define('SECURE_AUTH_SALT', 'hm#Z%O!X_mr?lM|>>~r-?F%wi R($}|9R[):4^NTsj+gS[qnv}7|+0<9e-$DJjju');
define('LOGGED_IN_SALT', 'tyPHBOCkXZh_4H;G|^.&|^#JPB/f;{}y_Orj!6AH?#wovx+KKtTZ A[HMS9SZJ|N');
define('NONCE_SALT', 'Eb-/t 5D-vPV9I--8F<[^lcherGv.g+|7p6;+xP|5g6P}tup1K.vuHAQ=uWZ#}H^');
The variable is defined like so:
KEY=$(cat keyfile)
I used the following sed syntax:
sed -i "s/stringtoreplace/$KEY/" /path/to/file
I've also tried different variations, using single-quotes, quotes around the variables
sed -i "s/stringtoreplace/"$KEY"/" /path/to/file
sed -i "s/stringtoreplace/"${KEY}"/" /path/to/file
sed -i "s/stringtoreplace/'$KEY'/" /path/to/file
I think I "brute-forced" every way possible to put quotes and I don't know how to escape randomly generated characters like those. I keep getting the following error:
unterminated s command
Any suggestions on how to replace the string with the weird-hash-like variable?
sed is an excellent tool for simple substitutions on a single line but for anything else you should use awk:
awk -v key="$KEY" '{sub(/stringtoreplace/,key)}1' file
That will work no matter what characters "$KEY" contains, except for "&".
One possibility is to use bash instead of sed. That makes the substitution easy, but you'll have to emulate the -i option.
Something like this:
TMPFILE=$(mktemp)
KEY=$(cat keyfile)
while IFS= read -r LINE; do
echo "${LINE//stringtoreplace/$KEY}"
done </path/to/file >$TMPFILE
mv $TMPFILE /path/to/file
Try this:
KEY=$(cat keyfile | sed -e 's/[]\/()$*.^|[]/\\&/g')
sed -i "s/stringtoreplace/$KEY/" /path/to/file
The problem is that the $KEY variable contains slashes, which are the delimiters for your s command.
sed can do more than search and replace:
sed '/stringtoreplace/{
d
r keyfile
}' /path/to/file
I'm assuming "stringtoreplace" occurs by itself on a line.
Suppose my file a.conf is as following
Include /1
Include /2
Include /3
I want to replace "Include /2" with a new line, I write the code in .sh file :
line="Include /2"
rep=""
sed -e "s/${line}/${rep}/g" /root/new_scripts/a.conf
But after running the sh file, It give me the following error
sed: -e expression #1, char 14: unknown option to `s'
If you are using a newer version of sed you can use -i to read from and write to the same file. Using -i you can specify a file extension so a backup will be made, incase something went wrong. Also you don't need to use the -e flag unless you are using multiple commands
sed -i.bak "s/${line}/${rep}/g" /root/new_scripts/a.conf
I have just noticed that as the variables you are using are quoted strings you may want to use single quotes around your sed expression. Also your string contains a forward slash, to avoid any errors you can use a different delimiter in your sed command (the delimiter doesn't need to be a slash):
sed -i.bak 's|${line}|${rep}|g' /root/new_scripts/a.conf
You have to write the changes to a new file and then, move the new file over the old one. Like this:
line="Include 2"
rep=""
sed -e "s/${line}/${rep}/g" /root/new_scripts/a.conf > /root/new_scripts/a.conf-new
mv /root/new_scripts/a.conf-new /root/new_scripts/a.conf
The redirection (> /root/new_scripts/a.conf) wipes the contents of the file before sed can see it.
You need to pass the -i option to sed to edit the file in-place:
sed -i "s/${line}/${rep}/g" /root/new_scripts/a.conf
You can also ask sed to create a backup of the original file:
sed -i.bak "s/${line}/${rep}/g" /root/new_scripts/a.conf
So, if you have to replace a substring in a file, you can use sed command like this, say we have a file as file.txt, so replacing a substring in it can be done like this
searchString="abc";
replaceString="def";
sed -i '' "s|$searchString|$replaceString|g" file.txt
This will all the occurrences of "abc" with "def" in file.txt. Also, this keeps a check for any / character present in the variables used, and with no backup file made.
I have a large number of words in a text file to replace.
This script is working up until the sed command where I get:
sed: 1: "*.js": invalid command code *
PS... Bash isn't one of my strong points - this doesn't need to be pretty or efficient
cd '/Users/xxxxxx/Sites/xxxxxx'
echo `pwd`;
for line in `cat myFile.txt`
do
export IFS=":"
i=0
list=()
for word in $line; do
list[$i]=$word
i=$[i+1]
done
echo ${list[0]}
echo ${list[1]}
sed -i "s/{$list[0]}/{$list[1]}/g" *.js
done
You're running BSD sed (under OS X), therefore the -i flag requires an argument specifying what you want the suffix to be.
Also, no files match the glob *.js.
This looks like a simple typo:
sed -i "s/{$list[0]}/{$list[1]}/g" *.js
Should be:
sed -i "s/${list[0]}/${list[1]}/g" *.js
(just like the echo lines above)
So myFile.txt contains a list of from:to substitutions, and you are looping over each of those. Why don't you create a sed script from this file instead?
cd '/Users/xxxxxx/Sites/xxxxxx'
sed -e 's/^/s:/' -e 's/$/:/' myFile.txt |
# Output from first sed script is a sed script!
# It contains substitutions like this:
# s:from:to:
# s:other:substitute:
sed -f - -i~ *.js
Your sed might not like the -f - which means sed should read its script from standard input. If that is the case, perhaps you can create a temporary script like this instead;
sed -e 's/^/s:/' -e 's/$/:/' myFile.txt >script.sed
sed -f script.sed -i~ *.js
Another approach, if you don't feel very confident with sed and think you are going to forget in a week what the meaning of that voodoo symbols is, could be using IFS in a more efficient way:
IFS=":"
cat myFile.txt | while read PATTERN REPLACEMENT # You feed the while loop with stdout lines and read fields separated by ":"
do
sed -i "s/${PATTERN}/${REPLACEMENT}/g"
done
The only pitfall I can see (it may be more) is that if whether PATTERN or REPLACEMENT contain a slash (/) they are going to destroy your sed expression.
You can change the sed separator with a non-printable character and you should be safe.
Anyway, if you know whats on your myFile.txt you can just use any.