I have string say e.g. ab_abc_bbb_ccc_ssss_pppp, I want the word after ccc i.e. ssss from the string, how to achieve the same using unix command
you mean something like this?
echo "ab_abc_bbb_ccc_ssss_pppp" | sed 's/.*ccc_\([^_]*\).*/\1/'
explanation
s/ # substitute
.*ccc_ # find search pattern
\([^_]*\) # save all chars without '_' into arg1 (\1)
_.*/ # ignore trailing chars
\1/ # print \1
output
ssss
Related
I'm trying to remove all white spaces before and after 3 consecutive periods and replace it with the actual ellipse symbol.
I've tried the following code:
sed 's/[[:space:]]*\.\.\.[[:space:]]*/…/g'
It replaces the 3 periods with the ellipse symbol, but the spaces before and after remain.
Sample Input.
hello ... world
Desired output
hello…world
Expression you are using is ERE(extended regular expressions) you have to add -E option to sed as follows to allow it, since you are using character classes in your code [[:space:]].
sed -E 's/[[:space:]]*\.\.\.[[:space:]]*/.../g' Input_file
Without -E try:
sed 's/ *\.\.\. */.../g' Input_file
Here is another sed
echo "hello ... world" | sed -E 's/ +(\.\.\.) +/\1/g'
hello...world
4 dots, do nothing?
echo "hello .... world" | sed -E 's/ +(\.\.\.) +/\1/g'
hello .... world
In bash, just use parameter substitution...
foo="hello ... world"
foo="${foo//+( )...+( )/...}"
Now, echo "$foo", outputs:
hello...world
The syntax for BaSH regex variable substitution are as follows:
${var-name/search/replace}
A single /replaces only the first occurrence from the left, while a double //replaces every occurrence.
One of ?*+#! followed by (pattern-list) replaces a specified number of occurrences of the patterns in pattern-list as follows:
? Zero or one occurrence
* Zero or more occurrences
+ One or more occurrences
# A single occurence
! Anything that *doesn't* match one of the occurrences
Pattern list can be any combination of literal strings, or character classes, separated by the pipe character |
I have SNMP outputs like:
IP-MIB::ipNetToMediaPhysAddress.5122.192.19.3.25 = STRING: 34:8:4:56:f4:70
As you can see mac-address output is incorrect, and i fix it with sed:
echo IP-MIB::ipNetToMediaPhysAddress.5122.192.19.3.25 = STRING: 34:8:4:56:f4:70 |
sed -e 's/\b\(\w\)\b/0\1/g'
Output:
IP-MIB::ipNetToMediaPhysAddress.5122.192.19.03.25 = STRING: 34:08:04:56:f4:70
It fixes address but changes IP as well from 192.19.3.25 to 192.19.03.25. How can I avoid it and force to perform sed only after STRING: or only after last space in the string ?
The MAC address is colon-separated. You can use that to limit the substitutions. This will perform the substitutions that you are interested in but only if the word character is next to a colon:
sed -e 's/\b\w:/0&/g; s/:\(\w\)\b/:0\1/g'
For example:
$ echo IP-MIB::ipNetToMediaPhysAddress.5122.192.19.3.25 = STRING: 34:8:4:56:f4:70 | sed -e 's/\b\w:/0&/g; s/:\(\w\)\b/:0\1/g'
IP-MIB::ipNetToMediaPhysAddress.5122.192.19.3.25 = STRING: 34:08:04:56:f4:70
How it works
s/\b\w:/0&/g
This performs the substitution if the word character is preceded by a word break, \b, and followed by a colon. Since we just need to put a zero in front of the entire matched text, not just some section of it, we can omit the parens and just use & to copy the matched text.
s/:\(\w\)\b/:0\1/g
If there are any remaining substitutions that need to be done where the word character is preceded by a colon and followed by a word break, this does them.
Note: We are using GNU extensions that may not be portable.
Another way with sed if the MAC address is at end of line
echo IP-MIB::ipNetToMediaPhysAddress.5122.192.19.3.25 = STRING: 4:8:d:56:f4:7 |
sed -E '
s/$/:/
:A
s/([^[:xdigit:]])([[:xdigit:]]:)/\10\2/
tA
s/:$//'
For example, I have a file containing a line as below:
"abc":"def"
I need to insert 123 between "abc":" and def" so that the line will become: "abc":"123def".
As "abc" appears only once so I think I can just search it and do the insertion.
How to do this with bash script such as sed or awk?
AMD$ sed 's/"abc":"/&123/' File
"abc":"123def"
Match "abc":", then append this match with 123 (& will contain the matched string "abc":")
If you want to take care of space before and after :, you can use:
sed 's/"abc" *: *"/&123/'
For replacing all such patterns, use g with sed.
sed 's/"abc" *: *"/&123/g' File
sed:
$ sed -E 's/(:")(.*)/\1123\2/' <<<'"abc":"def"'
"abc":"123def"
(:") gets :" and put in captured group 1
(.*) gets the remaining portion and put in captured group 2
in the replacement, \1123\2 puts 123 between the groups
awk:
$ awk -F: 'sub(".", "&123", $2)' <<<'"abc":"def"'
"abc" "123def"
In the sub() function, the second ($2) field is being operated on, pattern is used as . (which would match "), and in the replacement the matched portion (&) is followed by 123.
echo '"abc":"def"'| awk '{sub(/def/,"123def")}1'
"abc":"123def"
I have a file (/tmp/test) the has a the string "aaabbbccc" in it
I want to extract "bbb" from the string with sed.
Doing this returns the entire string:
sed -n '/aaa/,/ccc/p' /tmp/test
I just want to return bbb from the string with sed (I am trying to learn sed so not interested in other solutions for this)
Sed works on a line basic, and a,b{action} will run action for lines matching a until lines matching b. In your case
sed -n '/aaa/,/ccc/p'
will start printing lines when /aaa/ is matched, and stop when /ccc/ is matched which is not what you want.
To manipulate a line there is multiply options, one is s/search/replace/ which can be utilized to remove the leading aaa and trailing ccc:
% sed 's/^aaa\|ccc$//g' /tmp/test
bbb
Breakdown:
s/
^aaa # Match literal aaa in beginning of string
\| # ... or ...
ccc$ # Match literal ccc at the end of the sting
// # Replace with nothing
g # Global (Do until there is no more matches, normally when a match is
# found and replacement is made this command stops replacing)
If you are not sure how many a's and c's you have you can use:
% sed 's/^aa*\|cc*$//g' /tmp/test
bbb
Which will match literal a followed by zero or more a's at the beginning of the line. Same for the c's but just at the end.
With GNU sed:
sed 's/aaa\(.*\)ccc/\1/' /tmp/test
Output:
bbb
See: The Stack Overflow Regular Expressions FAQ
Assume the substring is unique, for example, given string,
"123 main streetHuntington, WV"
How could I locate the Huntington and add a white space before it.
"123 main street Huntington, WV"
If you are parsing arbitrary addresses, this is a very hard problem.
Assuming you're not just trying to put a space in that specific string, you might want to add a space before an uppercase letter that is preceded by a lower case letter.
sed -r 's/([[:lower:]])([[:upper:]])/\1 \2/g'
# perl
echo "123 main streetHuntington, WV" | perl -ne 's/(Huntington)/ $1/;print'
# sed
echo "123 main streetHuntington, WV" | sed 's/\(Huntington\)/ \1/'