Assume a file with the following contents:
good
good bad
next of baaaad
good
I want to use sed to delete lines which contain "bad" and the next line of these lines. In above example I want to delete line 2 and line 3.
How can I do that?
I tried this, but it doesn't work:
ebra#him:/tmp$ cat iio | sed -e "s/\n.*bad.*\n.*//"
good
good bad
next of baaaad
good
In sed:
sed '/bad/{N;d}' Input_file
Following awk may help you here.
awk '/bad/{getline;next} 1' Input_file
give this one-liner a try:
sed '/bad/{N;d}' file
for example:
kent$ cat f
1good
2good bad
3good --
4good
5bad
6good--
7good
kent$ sed '/bad/{N;d}' f
1good
4good
7good
sed -e '/bad/{N;d;}'
On a line that matches /bad/, append the next line to pattern space, then delete the whole thing.
With GNU sed, you can specify address ranges with matches and a number of lines following the match:
$ sed '/bad/,+1d' infile
good
good
Here is another sed command that works with gnu sed:
sed '/bad/,+1 d' file
good
good
This sed allows you to remove any number of lines after matching a pattern e.g. to delete 2 lines after match:
sed '/bad/,+2 d' file
Related
At the top of my HTML files, I have...
<H2>City</H2>
<P>Liverpool</P>
or
<H2>City</H2>
<P>Dublin</P>
I want to output the text between the tags straight after <H2>City</H2> instances. So in the examples above which are separate files, I want to print out Liverpool and in the second example, Dublin.
Looking at this thread, I try:
sed -e 's/City\(.*\)\/P/\1/'
which I hope would get me half way there... but that just prints out the entire file. Any ideas?
awk to the rescue! You need multi-char RS support though (gawk has it)
$ awk -F'[<>]' -v RS='<H2>City</H2>' 'NF{print $3}' file
another approach can be
$ awk 'c&&c--{sub(/<[^>]*>/,""); print} /<H2>City<\/H2>/{c=1}' file
find the next record after City and trim the angle brackets...
Try using the following regex :
(?s)(?<=City<\/H2>\n<P>).*?(?=<\/P>)
see regex demo / explanation
sed
sed -e 's/(?s)(?<=City<\/H2>\n<P>).*?(?=<\/P>)/'
I checked and the \s seem not work for spaces. You should use the newline character \n:
sed -e 's/<H2>City<\/H2>\n<P>\(.*\)<\/P>/\1/'
There is no need of use lookbehind (like above), that is an overkill.
With sed, you can use the n command to read next line after your pattern. Then just remove the tag to output your content:
sed -n '/<H2>City<\/H2>/n;s/ *<\/*P> *//gp;' file
I think this should work in your mac:
echo -e "<H2>City</H2>\n<P>Dublin</P>" |awk -F"[<>]" '/City/{getline;print $3}'
Dublin
I'm trying to remove everything but 3 separate lines with specific matching pattern and leave just the 3 lines I want
Here is my code;
sed -n '/matching pattern/matching pattern/matching pattern/p' > file.txt
If you have multiple commands on the same line, you need to separate the commands by a ;:
sed -n '/matching pattern/p;/matching pattern2/p;/matching pattern3/p' file
Alternatively you can put them onto separate lines:
sed -n '/matching pattern/p
/matching pattern2/p
/matching pattern3/p' file
Beside that, you can also use regex alternation:
sed -rn '/(pattern|pattern2|pattern3)/p' file
or (better) use grep:
grep -E '(pattern|pattern2|pattern3)' file
However, this might get messy if the patterns getting longer and more complicated.
awk to the rescue!
awk '/pattern1/ || /pattern2/ || /pattern3/' filename
I think it's cleaner than alternatives.
Sed with Deletion
There's always more than one way to do this sort of thing, but one useful sed programming pattern is using alternation with deletion. For example:
# BSD sed
sed -E '/root|daemon|nobody/!d' /etc/passwd
# GNU sed
sed -r '/root|daemon|nobody/!d' /etc/passwd
This makes it possible to express ideas like "delete everything except for the listed terms." Even when expressions are functionally equivalent, it can be helpful to use a construct that most closely matches the idea you're trying to convey.
This might work for you (GNU sed):
sed '/pattern1/b;/pattern2/b;/pattern3/b;d' file
The normal flow of sed is to print what remains in the pattern space after processing. Therefore if the required pattern is in the pattern space let sed do its thing otherwise delete the line.
N.B. the b command is like a goto and if it has no following identifier, it means break out of any further sed commands and print (or not print if the -n option is in action) the contents of the pattern space.
If I understood you correctly:
sed -n '/\(pattern1\|pattern2\|pattern3\)/p' file > newfile
I have a file containing strings of the following format:
05|KEEP|REDEFINES|NO_TYPE|PIC|9.
05|DELETE|REDEFINES|VARIABLE.
05|KEEP2|REDEFINES|VARIABLE2
|PIC|9(5).
I want to be able to use something like sed or awk to delete lines containing the word REDEFINES but NOT if the word PIC is also in there or if there is no full stop at the end of a line as this means the string has been split over 2 lines. So out of the 4 lines (3 strings) stated above I would only want to delete 05|DELETE|REDEFINES|VARIABLE.
I thought you might be able to use some kind of negation or lookahead but these don't seem to be available or I can't get them to work
Using awk this deletes anything containing REDEFINES in the String following the pattern in the example above:
awk '!/[[:print:]]*\REDEFINES[[:print:]]*\./'
Similarly using sed:
sed '/[[:print:]]*|REDEFINES[[:print:]]*\./d'
I just can't work out how to extend it to do what I need. Is this possible in sed or awk or do I need another tool?
Any help greatly appreciated.
Using awk
awk -v RS= '!/REDEFINES/ || /PIC/' file
05|KEEP|REDEFINES|NO_TYPE|PIC|9.
05|KEEP2|REDEFINES|VARIABLE2
|PIC|9(5).
Using sed (with older input data):
sed -i.bak '/REDEFINES/{/PIC/!d;}' file
05|KEEP|REDEFINES|NO_TYPE|PIC|9.
You can try the below command. Print the line if it contains PIC or if it does not contain REDEFINES. It is maintainable as it is not so tricky and could be understood without much of an effort.
cat input.txt | awk '{if ($0 ~ /PIC/ || $0 !~ /REDEFINES/){print $0}}'
Why don't you just use grep? Using negations on your question, here is what I understood:
keep the lines terminated with a full-stop, containing both REDEFINES and PIC.
So grep seems easy:
$ grep -E 'REDEFINES.*\.$' file | grep PIC
05|KEEP|REDEFINES|NO_TYPE|PIC|9.
Hope this helps.
This might work for you (GNU sed):
sed -r '/REDEFINES/{/PIC|[^.]$/!d}' file
or perhaps more easily:
sed '/PIC/b;/REDEFINES.*\.$/d' file
or if you prefer:
sed '/PIC/!{/REDEFINES.*\.$/d}' file
I am learning using sed in unix.
I have a file with many lines and I wanna delete all lines except lines containing strings(e.g) alex, eva and tom.
I think I can use
sed '/alex|eva|tom/!d' filename
However I find it doesn't work, it cannot match the line. It just match "alex|eva|tom"...
Only
sed '/alex/!d' filename
works.
Anyone know how to select lines containing more than 1 words using sed?
plus, with parenthesis like "sed '/(alex)|(eva)|(tom)/!d' file" doesn't work, and I wanna the line containing all three words.
sed is an excellent tool for simple substitutions on a single line, for anything else just use awk:
awk '/alex/ && /eva/ && /tom/' file
delete all lines except lines containing strings(e.g) alex, eva and tom
As worded you're asking to preserve lines containing all those words but your samples preserve lines containing any. Just in case "all" wasn't a misspeak: Regular expressions can't express any-order searches, fortunately sed lets you run multiple matches:
sed -n '/alex/{/eva/{/tom/p}}'
or you could just delete them serially:
sed '/alex/!d; /eva/!d; /tom/!d'
The above works on GNU/anything systems, with BSD-based userlands you'll have to insert a bunch of newlines or pass them as separate expressions:
sed -n '/alex/ {
/eva/ {
/tom/ p
}
}'
or
sed -e '/alex/!d' -e '/eva/!d' -e '/tom/!d'
You can use:
sed -r '/alex|eva|tom/!d' filename
OR on Mac:
sed -E '/alex|eva|tom/!d' filename
Use -i.bak for inline editing so:
sed -i.bak -r '/alex|eva|tom/!d' filename
You should be using \| instead of |.
Edit: Looks like this is true for some variants of sed but not others.
This might work for you (GNU sed):
sed -nr '/alex/G;/eva/G;/tom/G;s/\n{3}//p' file
This method would allow a range of values to be present i.e. you wanted 2 or more of the list then use:
sed -nr '/alex/G;/eva/G;/tom/G;s/\n{2,3}//p' file
I'd like to use sed to process a property file such as:
java.home=/usr/bin/java
groovy-home=/usr/lib/groovy
workspace.home=/build/me/my-workspace
I'd like to replace the .'s and -'s with _'s but only up to the ='s token. The output would be
java_home=/usr/bin/java
groovy_home=/usr/lib/groovy
workspace_home=/build/me/my-workspace
I've tried various approaches including using addresses but I keep failing. Does anybody know how to do this?
What about...
$ echo foo.bar=/bla/bla-bla | sed -e 's/\([^-.]*\)[-.]\([^-.]*=.*\)/\1_\2/'
foo_bar=/bla/bla-bla
This won't work for the case where you have more than 1 dot or dash one the left, though. I'll have to think about it further.
awk makes life easier in this case:
awk -F= -vOFS="=" '{gsub(/[.-]/,"_",$1)}1' file
here you go:
kent$ echo "java.home=/usr/bin/java
groovy-home=/usr/lib/groovy
workspace.home=/build/me/my-workspace"|awk -F= -vOFS="=" '{gsub(/[.-]/,"_",$1)}1'
java_home=/usr/bin/java
groovy_home=/usr/lib/groovy
workspace_home=/build/me/my-workspace
if you really want to do with sed (gnu sed)
sed -r 's/([^=]*)(.*)/echo -n \1 \|sed -r "s:[-.]:_:g"; echo -n \2/ge' file
same example:
kent$ echo "java.home=/usr/bin/java
groovy-home=/usr/lib/groovy
workspace.home=/build/me/my-workspace"|sed -r 's/([^=]*)(.*)/echo -n \1 \|sed -r "s:[-.]:_:g"; echo -n \2/ge'
java_home=/usr/bin/java
groovy_home=/usr/lib/groovy
workspace_home=/build/me/my-workspace
In this case I would use AWK instead of sed:
awk -F"=" '{gsub("\\.|-","_",$1); print $1"="$2;}' <file.properties>
Output:
java_home/usr/bin/java
groovy_home/usr/lib/groovy
workspace_home/build/me/my-workspace
This might work for you (GNU sed):
sed -r 's/=/\n&/;h;y/-./__/;G;s/\n.*\n//' file
"You wait ages for a bus..."
This works with any number of dots and hyphens in the line and does not require GNU sed:
sed 'h; s/.*=//; x; s/=.*//; s/[.-]/_/g; G; s/\n/=/' < data
Here's how:
h: save a copy of the line in the hold space
s: throw away everything before the equal sign in the pattern space
x: swap the pattern and hold
s: blow away everything after the = in the pattern
s: replaces dots and hyphens with underscores
G: join the pattern and hold with a newline
s: replace that newline with an equal to glue it all back together
Other way using sed
sed -re 's/(.*)([.-])(.*)=(.*)/\1_\3=\4/g' temp.txt
Output
java_home=/usr/bin/java
groovy_home=/usr/lib/groovy
workspace_home=/build/me/my-workspace
In case there are more than .- on left hand side then this
sed -re ':a; s/^([^.-]+)([\.-])(.*)=/\1_\3=/1;t a' temp.txt