Hi
I have a file with data arranged into columns. The first column is the chromosome name.
When I use grep to subset only rows with chr1, I get chr1 but also chr10, chr11,..
How do I get only rows with chr1?
grep chr1 filein > fileout
head fileout
chr1 59757841
chr11 108258691 ... (2 Replies)
Hi,
I'm struggling with a regex that would match a 'b' that follows an 'a' and is at the end of a string of non-white characters. For example:
Line 1: aba abab b abb aab bab baa
I can find the right strings but I'm lacking knowledge of how to "discard" the bits that precede bs.... (2 Replies)
Hi all,
any idea how to match the following:
char*<no or any string or space> buf and
char *<no or any string or space> buf
i need to capture the buf characters too.
currently i need two checks to cover this:
#search char* <any string> buf or char *<any string> buf
@noarray =... (2 Replies)
Hi all,
I am looking for a regex syntax to match repeated appearance. Likes,
']+]+' matches for string '65A SOME MORE AND 78B'
Now, this gets messy if I need to extract all such repeated appearance. I don't want to write ] four or five times for matching repeated appearance.
Thanks in... (2 Replies)
I am trying to match a similar line using grep with regular expression
the line is
/remote/mac/pbbbb/abc/def/hij/hop/include/abc/tif/element/test/testfiles/Office.cpp:57: const OfficeType& getType().get() const;
I just need to extract the bold characters using grep with regular expression.... (5 Replies)
hi everyone
suppose we have two scenario
echo ABCD | grep \{4\}
DATE
echo SYSDATE | grep \{4\}
SYSDATE
i want to match the string of four length only please help (5 Replies)
I've found this script which seems very promising to solve my issue:
To search and replace many different database passwords in many different (.php, .pl, .cgi, etc.) files across my filesystem.
The passwords may or may not be contained within quotes, single quotes, etc.
#!/bin/bash... (4 Replies)
echo 20110101 | awk '{ print match($0,/^((17||18||19||20)|)-*(|0|1)-*(|0||3)$/))
I am getting a match for the above, where as it shouldn't, as there is no hyphen in the echoed date.
Another question is what is the difference between || and | in the above statement (4 Replies)
Hi
I'd like to add the newline:
\tuser: nobody", or "<TAB>user: nobody
to all files named:
docker-compose.ymlin subfolders of pwd with names beginning with 10-20.
Within these files, I'd like to find the line (there'll only be one) containing:
command: celery workerNOTE: As far as... (2 Replies)
Discussion started by: duncanbetts
2 Replies
LEARN ABOUT BSD
egrep
GREP(1) General Commands Manual GREP(1)NAME
grep, egrep, fgrep - search a file for a pattern
SYNOPSIS
grep [ option ] ... expression [ file ] ...
egrep [ option ] ... [ expression ] [ file ] ...
fgrep [ option ] ... [ strings ] [ file ]
DESCRIPTION
Commands of the grep family search the input files (standard input default) for lines matching a pattern. Normally, each line found is
copied to the standard output. Grep patterns are limited regular expressions in the style of ex(1); it uses a compact nondeterministic
algorithm. Egrep patterns are full regular expressions; it uses a fast deterministic algorithm that sometimes needs exponential space.
Fgrep patterns are fixed strings; it is fast and compact. The following options are recognized.
-v All lines but those matching are printed.
-x (Exact) only lines matched in their entirety are printed (fgrep only).
-c Only a count of matching lines is printed.
-l The names of files with matching lines are listed (once) separated by newlines.
-n Each line is preceded by its relative line number in the file.
-b Each line is preceded by the block number on which it was found. This is sometimes useful in locating disk block numbers by con-
text.
-i The case of letters is ignored in making comparisons -- that is, upper and lower case are considered identical. This applies to
grep and fgrep only.
-s Silent mode. Nothing is printed (except error messages). This is useful for checking the error status.
-w The expression is searched for as a word (as if surrounded by `<' and `>', see ex(1).) (grep only)
-e expression
Same as a simple expression argument, but useful when the expression begins with a -.
-f file
The regular expression (egrep) or string list (fgrep) is taken from the file.
In all cases the file name is shown if there is more than one input file. Care should be taken when using the characters $ * [ ^ | ( ) and
in the expression as they are also meaningful to the Shell. It is safest to enclose the entire expression argument in single quotes ' '.
Fgrep searches for lines that contain one of the (newline-separated) strings.
Egrep accepts extended regular expressions. In the following description `character' excludes newline:
A followed by a single character other than newline matches that character.
The character ^ matches the beginning of a line.
The character $ matches the end of a line.
A . (period) matches any character.
A single character not otherwise endowed with special meaning matches that character.
A string enclosed in brackets [] matches any single character from the string. Ranges of ASCII character codes may be abbreviated
as in `a-z0-9'. A ] may occur only as the first character of the string. A literal - must be placed where it can't be mistaken as
a range indicator.
A regular expression followed by an * (asterisk) matches a sequence of 0 or more matches of the regular expression. A regular
expression followed by a + (plus) matches a sequence of 1 or more matches of the regular expression. A regular expression followed
by a ? (question mark) matches a sequence of 0 or 1 matches of the regular expression.
Two regular expressions concatenated match a match of the first followed by a match of the second.
Two regular expressions separated by | or newline match either a match for the first or a match for the second.
A regular expression enclosed in parentheses matches a match for the regular expression.
The order of precedence of operators at the same parenthesis level is [] then *+? then concatenation then | and newline.
Ideally there should be only one grep, but we don't know a single algorithm that spans a wide enough range of space-time tradeoffs.
SEE ALSO ex(1), sed(1), sh(1)DIAGNOSTICS
Exit status is 0 if any matches are found, 1 if none, 2 for syntax errors or inaccessible files.
BUGS
Lines are limited to 256 characters; longer lines are truncated.
4th Berkeley Distribution April 29, 1985 GREP(1)