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 V7
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; unless the -h flag is used, the file name is shown if there is more than one input file.
Grep patterns are limited regular expressions in the style of ed(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.
-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 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.
-s No output is produced, only status.
-h Do not print filename headers with output lines.
-y Lower case letters in the pattern will also match upper case letters in the input (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.
-x (Exact) only lines matched in their entirety are printed (fgrep only).
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 matches that character.
The character ^ ($) matches the beginning (end) of a line.
A . 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 * (+, ?) matches a sequence of 0 or more (1 or more, 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.
SEE ALSO ed(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
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.
Lines are limited to 256 characters; longer lines are truncated.
GREP(1)