I have a short text file with the following syntax:
FileName: some name
Version: 3
Length: 45
hello, this is an irrelevant, unimportant text.
So is this line.
Now, I'm trying to write a script that replace the version number with a given new number.
Anyone knows how to? I really don't mind it to be ugly
thanks,
Udi
Why not just use sed?
sed -i 's/^Version: .*$/Version: 99/' foo.txt
I don't know how to do it in csh. However, at the risk of coming across as one of those annoying people who tells you to use their favourite thing at every opportunity, there are better ways than using csh. The traditional unix command sed is good at this stuff, or a language like Perl is also useful.
perl -p -i -e 's/Version: 3/Version: 4/g;' myfile
should do it.
Related
Here I am, new and wet behind the ears to Bash/Shell Scripting.
Basically I am needing to know how to utilize sed in this instance on one of two very basic scripts. The intention is to retrieve disk usage info based on username/domain name.
You might be asking why two of the same scripts?
Given I work with many username/domains, the default domain_usage will be be overwritten into to domain_usage_tmp as and when username/domain changes. I have tried using sed to substitute, which has not provided the intended results:
sed 's/username/x/g' 's/domain/x/g' /scripts/domain_usage_tmp
Provide me with knowledge and wisdom :-)
Perhaps you forget to use the -i option:
man sed
...
-i[SUFFIX], --in-place[=SUFFIX]
edit files in place (makes backup if SUFFIX supplied)
sed -i 's/username/x/g' 's/domain/x/g' /scripts/domain_usage_tmp
Let's say we have a file that contains
HHEELLOO
HHYYPPOOTTHHEESSIISS
and we want to delete repeated characters. To my knowledge we can do this with
s/\([A-Z]\)\1/\1/g
This is a homework problem and the professor said he wants us to try the exercises without back-referencing or extended regular expressions. Is that possible on this one? I would appreciate it if anyone could point me in the right direction, thanks!
The only reasonable way to do this is to use the right tool for the job, in this case tr:
$ tr -s 'A-Z' < file
HELO
HYPOTHESIS
If you were going to use sed for that specific problem though then it'd just be:
$ sed 's/\(.\)./\1/g' file
HELO
HYPOTHESIS
If that's not what you're looking for then edit your question to show more truly representative sample input and expected output.
Here's one way:
s/AA/A/g
s/BB/B/g
...
s/ZZ/Z/g
As a one-liner:
sed 's/AA/A/g; s/BB/B/g; ...'
Using standard Unix tools how can I search in a text file or output for a word with maybe 1-2 letters transposed or missed?
For example my input
function addtion(number, increment)
return number+increment
end
function additoin(number, increment)
return number+increment
end
I would like to search for addition and match addtion and additoin in my input and tell me about it. Because it's code, checking against dictionary is out of the question.
Currently cat file.txt | grep "addition" will simply yield me nothing.
You can play around with the agrep command. It can perform fuzzy, approximate matches.
The following command worked for me:
agrep -2 addition file
You can't do a fuzzy match with standard grep, but if there are specific misspelling you're interested in, you could construct a regular expression that matches those.
For example:
grep add[it]*on
matches the example misspelling you gave. But that's probably not general enough for your purposes.
A better approach is likely going to be to use some sort of static analysis tool specific to the language the code is in. It might not give you the right spelling, but should be able to tell you where the function name and calls to the function use different spellings.
Try the spell command. Note: You might need a dictionary (usually aspell-en in your distro's repositories).
As the answer says, you should definitely try agrep. In addition, there is a newer and much faster alternative ugrep for fuzzy search. Use -Z2 to allow up to 2 errors:
ugrep -Z2 addition file.txt
An insertion, deletion, or substitution is one error. A transposition (as in additoin) counts as two errors, i.e. two substitutions. Use option -i for case-insensitive search and -w to match whole words.
Try this on linux terminal:
grep -rnw "text" ./
I once found a built-in command that would take a prefix as an argument and return all words that could complete that word. So for example,
>> COMMAND cali
California
calibrate
calibration
........
of course it would list a lot more words, in alphanumerical order. It was really useful, and optionally took a file other than the default to look in.
I'm not just trying to produce this behavior: there are obviously a million ways to use grep, sed, awk, perl, or INSERT TURING-COMPLETE LANGUAGE HERE to get this. I'm looking for the command.
Unfortunately it's hard to google something when you don't remember the name, but while it might not have been POSIX standard it was definitely a very common Linux utility, does anyone know what this was called?
Found it: it's called look, and it seems to have been around Unix since V7. (The man page is dated 1993!)
It does a binary search on the optional second argument to find all matches, defaulting to /usr/share/dict/words.
Not really a builtin command, but there is /usr/share/dict/* and grep:
$ grep -i '^Cali' /usr/share/dict/words
Caliban
Calibanism
caliber
calibered
calibogus
calibrate
calibration
calibrator
calibre
Caliburn
...
I'm stuck in this very easy problem (I hope it is for you).
I need to substitute several strings with special characters in a huge file.
I'm trying using sed and bash because I'm a linux user but I've only used sed for "standard" string so far.
These are the kind of strings that I'm trying to manipulate
(alpha[1],alpha[2]) and diff(A45(i,j),alpha[1])
and the substituting strings would be
(i,j) and dzA45(i,j)
I tried sed -i 's/(alpha[1],alpha[2])/(i,j)/g' $filetowork and
sed -i 's/\(alpha\[1\],alpha\[2\]\)/i,j/g' $filetowork without any success
The second option seems to work for the first kind of string but it doesn't for the second one, why?
could you please help me? I took a look around stackoverflow old questions without any help, unfortunately :(
I just tried on the command line, but
echo "(alpha[1],alpha[2])" | sed 's/(alpha\[1\],alpha\[2\])/(i,j)/
worked for the first case. Please note that you should not escape ( or ), because that is how you activate groups.
For the second one
echo "diff(A45(i,j),alpha[1])" | sed 's/diff(A45(i,j),alpha\[1\])/dzA45(i,j)/'
worked for me. The same case, don't escape brackets!