hi all...
i have the next question:
i have a flat file with a lot of records (lines). Each record has 10 fields, which are separated by pipe (|). My problem is what sometimes, in the first record, there are white spaces (no values, nothing) in the beginning of the record, like this:
ws ws... (2 Replies)
I have a variable that calls in a string from txt file. Problem is the string comes with an abundance of white spaces trailing it. Is there any easy way to trim the tailing white spaces off at the end? Thanks in advance. (9 Replies)
Hi,
Can anybody suggest me how to combine two strings with two or more white spaces and assign it to a variable?
E.g.
first=HAI
second=HELLO
third="$first $second" # appending strings with more than one white spaces
echo $third
this would print
HAI HELLO
Output appears... (2 Replies)
Hi,
I have a file that has multiple spaces between characters. I want to delete or convert the multiple spaces into a single space. I think this can be done in "sed" but I only know the syntax to delete trailing or leading spaces. Can this be done with "sed" or awk?
I have a file that looks... (6 Replies)
Hello Guys,
I am a newbie to unix. I am having a requirement. Please help me for finding a solution for this,
I am having a file as mentioned below:
$ cat shank
ackca
acackac akcajc akcjkcja akcj
ckcklc
I want to delete all the white spaces in this file,
I tried... (2 Replies)
Hello dear community!
I've recently written a BASH function for auto completion of options. It works like following: if a user types a command and then an argument to this command which starts with "^-" and then presses TAB, then 'user_command --help (or -h)' is invoked and possible options are... (0 Replies)
Hi All,
I am facing issues converting white spaces and tabs together in a file I am reading. Here is the command I am trying:
tr -s ' '@ | sort -t@ +1n filename
I guess the problem is that it is not converting the tabs to another delimiter. Also, I am supposed to accomplish this only using... (5 Replies)
Hi,
I am having problem in deleting the leading spaces:-
cat x.csv
baseball,NULL,8798765,Most played
baseball,NULL,8928192,Most played
baseball,NULL,5678945,Most played
cricket,NOTNULL,125782,Usually played
cricket,NOTNULL,678921,Usually played
$ nawk 'BEGIN{FS=","}!a... (2 Replies)
Hi;
In following code
find LOG_DIR -type f | while read filename; do echo $filename; done
I want to precede each white space encountered in filename with \ so that when i use $filename for running some commands in do...done,it wont give me an error.
will appreciate ur help in this.... (1 Reply)
Hello!
I have one problem with my bash script - I would like to be able to read white space characters from stdin (for example single " ") - can I acomplish that somehow? I need to read only one character at the time, so I use read -s -n 1 var but it doesn't work for whitespaces apparently.
... (3 Replies)
Discussion started by: xqwzts
3 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)