Yesterday I was looking for a way to grep for a tab in the shell, and found this solution in several places:
I'm fine with most of this, but I don't understand what the $ (dollar sign) before the first quote does. It doesn't work without, but I couldn't find any explanation in the grep man or info pages. The only mention of $ there is as a meta-character that matches the end of a regular expression.
Can someone explain and/or point me to other documentation where I can read it up?
Hi
I was wondering if it's possible to use a command to get the first 3 characters of a line in a text file, I tried grep but it returns the whole line but I am only interested in the first 3 characters. Is this possible with grep or I need any other command?
Also is it possible deleting from... (2 Replies)
I must remove hex characters 0A and 0D from several fields within an MS Access Table. Since I don't think it can be done in Access, I am trying here.
I am exporting a Table from Access (must be fixed length fields, I think, for my idea to work here) into a text format.
I then want to run a... (2 Replies)
Hi friends,
I want your help.
I have a flat file. I want a script to search following pattern in it and once it get that pattern it should grep next 7 characters from it and should keep it in output file output.TXT
Pattern is
RSTD3R0*******
In above example, characters in the place of *... (3 Replies)
Hi All,
My main intension of is to convert the Hexstring stored in a char* into hex and then prefixing it with "0x" and suffix it with ','
This has to be done for all the hexstring char* is NULL.
Store the result prefixed with "0x" and suffixed with ',' in another char* and pass it to... (1 Reply)
Hello All,
I have a requirement where I need to replaced the hex character - '\x0D' with 2 hex characters - 'x0D' & 'x0A'
I am trying to use SED -
But somehow its not working. Any pointers?
Also the hex character '\x0D' can occur anywhere in the line.
Can this also be accomplished... (6 Replies)
Hi,
I am a bit stuck with displaying characters. I am having values like below in the proper displayable characters. which I would want to print the actual value on the right hand side. I dont want to create an array because I would have to create 255 different values. isnt there another way of... (17 Replies)
I have the following file consisting of dates and sample measurements:
05��Oct��2010 1.31��
06��Oct��2010 1.32��
07��Oct��2010 1.31��
The hex characters are \xc2\xa0 in sequence.
I have tried to remove the characters as follows:
sed -i '' -e 's/\xc2\xa0//g' file.dat
and as follows... (6 Replies)
Hi guys,
First off, i'm a complete noob to UNIX and LINUX so apologies if I don't understand the basics!
I have a file which contains a hex value of '0D' at the end of each line when I look at it in a hex viewer.
I need to change it so it contains a hex value of '0D0A0A'
I thought... (10 Replies)
Discussion started by: AndyBSG
10 Replies
LEARN ABOUT BSD
grep
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)