Sed: can't define the pattern correctly, can you please assist? - sed

I'm trying to add "ARG1$" to the end of this line:
command[check_net_speed]=/usr/lib64/nagios/plugins/check_net_speed.sh $
I've tried:
sed -e 's/^command\[check_net_speed\]$/$ARG1$/g' /etc/nagios/nrpe.cfg
sed -e 's/.*speed.*/$ARG1$/g' /etc/nagios/nrpe.cfg
But none did the trick... what's the right way to catch the pattern of the "check_net_speed" command and add "ARG1$" at the end of the line, so the line will look like this:
command[check_net_speed]=/usr/lib64/nagios/plugins/check_net_speed.sh $ARG1$


Something like
sed -e 's/^command\[check_net_speed\].*/&ARG1$/g' input
command[check_net_speed]=/usr/lib64/nagios/plugins/check_net_speed.sh $ARG1$


Change your sed command like below,
sed -e '/^command\[check_net_speed\]/s~$~ARG1$~' file
/^command\[check_net_speed\]/ matches the lines which starts with command[check_net_speed] and it do the replacement on those matched lines.
$ in the regex part means end of the line. So the above command replaces the end of the line anchor with ARG1$
Example:
$ echo 'command[check_net_speed]=/usr/lib64/nagios/plugins/check_net_speed.sh $' | sed -e '/^command\[check_net_speed\]/s~$~ARG1$~'
command[check_net_speed]=/usr/lib64/nagios/plugins/check_net_speed.sh $ARG1$


$ has a special meaning: end of line. To treat it as a literal, you have to escape it:
sed '/^command\[check_net_speed\].*\$/s/$/ARG1$/' file
This will replace the end of line (indicated by $ alone) with the string ARG1$. So at the end, ARG1$ will be appended to the line.
The /command/ part is used to perform this replacement only in the lines containing the string command.
Test
$ cat a
command[check_net_speed]=/usr/lib64/nagios/plugins/check_net_speed.sh $
ddd
$ sed '/^command\[check_net_speed\].*\$/s/$/ARG1$/' a
command[check_net_speed]=/usr/lib64/nagios/plugins/check_net_speed.sh $ARG1$
ddd


As a supplement to nu11p01n73R's answer. Use
sed -e 's/^command\[check_net_speed\].*\$$/&ARG1$/g;q' /etc/nagios/nrpe.cfg
;q after substitution command means stop processing the rest of this file after first match.

Related

How do I join the previous line with the current line with sed?

I have a file with the following content.
test1
test2
test3
test4
test5
If I want to concatenate all lines into one line separated by commas, I can use vi and run the following command:
:%s/\n/,/g
I then get this, which is what I want
test1,test2,test3,test4,test5,
I'm trying to use sed to do the same thing but I'm missing some unknown command/option to make it work. When I look at the file in vi and search for "\n" or "$", it finds the newline or end of line. However, when I tell sed to look for a newline, it pretends it didn't find one.
$ cat test | sed --expression='s/\n/,/g'
test1
test2
test3
test4
test5
$
If I tell sed to look for end of line, it finds it and inserts the comma but it doesn't concatenate everything into one line.
$ cat test | sed --expression='s/$/,/g'
test1,
test2,
test3,
test4,
test5,
$
What command/option do I use with sed to make it concatenate everything into one line and replace the end of line/newline with a comma?

sed reads one line at a time, so, unless you're doing tricky things, there's never a newline to replace.
Here's the trickiness:
$ sed -n '1{h; n}; H; ${g; s/\n/,/gp}' test.file
test1,test2,test3,test4,test5
h, H, g documented at https://www.gnu.org/software/sed/manual/html_node/Other-Commands.html
When using a non-GNU sed, as found on MacOS, semi-colons before the closing braces are needed.
However, paste is really the tool for this job
$ paste -s -d, test.file
test1,test2,test3,test4,test5
If you really want the trailing comma:
printf '%s,\n' "$(paste -sd, file)"

tr instead of sed for this one:
$ tr '\n' ',' < input.txt
test1,test2,test3,test4,test5,
Just straight up translate newlines to commas.

Based on how can i replace each newline n with a space using sed:
sed -e ':a' -e 'N' -e '$!ba' -e 's/\n/,/g' <file>
testing:
$ cat file.txt
test1
test2
test3
test4
test5
$ sed -e ':a' -e 'N' -e '$!ba' -e 's/\n/,/g' file.txt
test1,test2,test3,test4,test5
Of course, if the question would have been more generic: How do I replace \n with any character using sed then one should only replace the , with ones desired char:
export CHAR_TO_REPLACE=','
export FILE_TO_PROCESS=<filename>
sed -e ':a' -e 'N' -e '$!ba' -e "s/\n/${CHAR_TO_REPLACE}/g" $FILE_TO_PROCESS
This answer is to satisfy the requirement of using sed. Otherwise, you can use alternatives like tr, awk etc.

This might work for you (GNU sed):
sed 'H;1h;$!d;x;y/\n/,/' file
Append all lines but the first to the hold space (the first replaces the hold space).
If it is not the last line of the file, delete it.
Otherwise, swap to the hold space and translate all newlines to commas.

Replace string and next one using sed

I know how to replace sting via sed:
sed -i "s|.*#app-${BRANCH}-log.*| Path ${LOG_PATH} #app-${BRANCH}-log|" /etc/td-agent-bit/td-agent-bit.conf
and this is work for file like
[INPUT]
Name tail
Path /var/lib/docker/containers/f774c1a3689dfffb2528833ac2ded629c3b1873fd3af96fe0cf1f041f22f88d8/f774c1a3689dfffb2528833ac2ded629c3b1873fd3af96fe0cf1f041f22f88d8-json.log #app-develop-log
Tag app.develop
Interval_Sec 1
but how to replace next line? for example:
#This line just for triggering sed
And this one must be replaced
Any idea? Sorry for my horrible English.

With GNU sed:
sed '/^#This line just for triggering sed$/{n;s/.*/foo/}' file
Output:
#This line just for triggering sed
foo
See: man sed

Replacing the test with sed

I'm trying to replace the text using the sed, but it's showing some error. Not getting where I'm getting wrong.
sed -i 's/process.env.REDIRECT_URI/http:\/\/test-domain.apps.io/\callback/g' input.txt
Have this :
process.env.REDIRECT_URI
Replace this with :
http://test-domain.apps.io

Try:
sed -i 's/process.env.REDIRECT_URI/http:\/\/test-domain.apps.io/g' input.txt
Notes:
The original command has a spurious string /\callback. All that was needed to make the code work was to remove it.
. is a wildcard. If you want to be sure that you are matching periods, they should be escaped:
sed -i 's/process\.env\.REDIRECT_URI/http:\/\/test-domain.apps.io/g' input.txt
Sometimes, its clearer if one doesn't have to escape /. One can use a separator of one's choice. For example, use #:
sed -i 's#process\.env\.REDIRECT_URI#http://test-domain.apps.io#g' input.txt
If you did want /callback in the output, use:
sed -i 's/process\.env\.REDIRECT_URI/http:\/\/test-domain.apps.io\/callback/g' input.txt
or:
sed -i 's#process\.env\.REDIRECT_URI#http://test-domain.apps.io/callback#g' input.txt

sed to copy part of line to end

I'm trying to copy part of a line to append to the end:
ftp://ftp.ncbi.nlm.nih.gov/genomes/all/GCA/900/169/985/GCA_900169985.1_IonXpress_024_genomic.fna.gz
becomes:
ftp://ftp.ncbi.nlm.nih.gov/genomes/all/GCA/900/169/985/GCA_900169985.1/GCA_900169985_IonXpress_024_genomic.fna.gz
I have tried:
sed 's/\(.*(GCA_\)\(.*\))/\1\2\2)'

$ f1=$'ftp://ftp.ncbi.nlm.nih.gov/genomes/all/GCA/900/169/985/GCA_900169985.1_IonXpress_024_genomic.fna.gz'
$ echo "$f1"
ftp://ftp.ncbi.nlm.nih.gov/genomes/all/GCA/900/169/985/GCA_900169985.1_IonXpress_024_genomic.fna.gz
$ sed -E 's/(.*)(GCA_.[^.]*)(.[^_]*)(.*)/\1\2\3\/\2\4/' <<<"$f1"
ftp://ftp.ncbi.nlm.nih.gov/genomes/all/GCA/900/169/985/GCA_900169985.1/GCA_900169985_IonXpress_024_genomic.fna.gz
sed -E (or -r in some systems) enables extended regex support in sed , so you don't need to escape the group parenthesis ( ).
The format (GCA_.[^.]*) equals to "get from GCA_ all chars up and excluding the first found dot" :
$ sed -E 's/(.*)(GCA_.[^.]*)(.[^_]*)(.*)/\2/' <<<"$f1"
GCA_900169985
Similarly (.[^_]*) means get all chars up to first found _ (excluding _ char). This is the regex way to perform a non greedy/lazy capture (in perl regex this would have been written something like as .*_?)
$ sed -E 's/(.*)(GCA_.[^.]*)(.[^_]*)(.*)/\3/' <<<"$f1"
.1

Short sed approach:
s="ftp://ftp.ncbi.nlm.nih.gov/genomes/all/GCA/900/169/985/GCA_900169985.1_IonXpress_024_genomic.fna.gz"
sed -E 's/(GCA_[^._]+)\.([^_]+)/\1.\2\/\1/' <<< "$s"
The output:
ftp://ftp.ncbi.nlm.nih.gov/genomes/all/GCA/900/169/985/GCA_900169985.1/GCA_900169985_IonXpress_024_genomic.fna.gz

Deleting lines begin with # but not the line #!/bin/ksh

How can I delete lines that begin with # but not #!/bin/ksh?
Using sed -e '/^#/ d' sed.sh will delete every line including #!/bin/ksh.

Thanks #Daniel H
sed -e '/#!\/bin\/ksh/p' -e '/^#/d' sed.sh
this is the command that gave the result I was looking for:

Like this:
sed '/^#/{/^#!\/bin\/ksh/d}' sed.sh
For all lines that start with a #, if they don't start with #!/bin/ksh, delete them.
Since comments (and the shebang line) might have spaces in front, more precise would be
sed '/^[[:space:]]*#/{/^[[:space:]]*#![[:space:]]*\/bin\/ksh/d}' sed.sh