sed uses regular expressions only, you can create a regex to look at the first field only with regex constructs; the ^ is already halfway there, as it forces the match to happen at beginning of line. Suppose the field separator is a vertical bar; then you can just add that after the string you want to search for, to anchor it properly.
This finds "AAA" followed by vertical bar, but only if it is at beginning of line (because of the ^) and ditto for "BBB".
The vertical bar has special meaning to some regular expression engines, just like the ^ -- if you get erratic behavior (all lines matching all the time) then you need to backslash-quote it, like \|. It is unfortunate that there are different dialects of sed so that we can't know for sure whether or not this is an issue in your case.
Last edited by era; 05-14-2008 at 05:52 AM..
Reason: Separator is vertical bar, as per above
Hello. I have an RS/6000 running AIX 4 and I need to be able to see if there are any users that are logged on more than once from the same terminal so I can kick them off to make room for other terminals. 64 connections is the limit. Currently I am doing this:
who | more
and then manually... (11 Replies)
Hi,
Let's say I have these 3 columns;
NGC1234 6 9
SL899 4 1
NGC1075 8 3
SL709 5 2
And I want to sort the data according to the first column (from a to z) like having them as:
NGC1075 8 3
NGC1234 6 9
SL709 5 2
SL899 4 1
Can that be done... (2 Replies)
Dear Gurus,
I need you to advice or suggestion about the best solution to copy data around 200-300G from serverA(location A) to serverB(location B). Normally, I will share folder and then copy but it takes too long time(about 2 days).
Do you have any suggestion or which way should be... (9 Replies)
Hello guys. I need help figuring this one out. It's probably really easy. Thanks in advance!
I have a file say for example containing this:
Rice Food
Carrots Food
Beans Food
Plates Kitchen
Fork Kitchen
Knives Kitchen
I need:
Food Rice, Carrots, Beans
Kitchen Plates, Fork,... (7 Replies)
I have the small script to arrange files of a descending way.
ls -l |sort -r -k4
i wanted for example if I place -d one arranges only the folders or -a to arranges only the files.
Cheers (7 Replies)
Hi All,
I have a long list made of 4 columns containing entries such as the following example:
a b c d
0 0 0 0
1 2 1 2
2 5 3 4
3 8 4 6
4 10 9 8
5 15 8 10So the top row is the header and I need to arrange the data in a way as to... (11 Replies)
My actual data looks like below
i have given only format. i can't give exact data format of my requirement due to some reasons. I this set of data lines about 5000
I need to come up with information in below
exact format of my data set :
Line<space>Number1<space>"somedata":... (1 Reply)
I am fairly new to unix scripting, the problem is i can understand the unix script. but i fail to write. I do not know where to start and how to end.
I am sure this forum will help to achive my dream scriptings in unix. Thanks in adv for your help.
Here I need.. I have list of columns in one... (2 Replies)
Hello,
I'm trying to create multiple commands using a variable input from another file but am not getting any successful results.
Basically, file1.txt contains multiple lines with single words:
<file1.txt>
yellow
blue
black
white
I want to create multiple echo commands with these... (8 Replies)
Hello,
I have some text data that is in the form of multi-line records. Each record ends with the string $$$$ and the next record starts on the next line.
RDKit 2D
15 14 0 0 0 0 0 0 0 0999 V2000
5.4596 2.1267 0.0000 C 0 0 0 0 0 0 0 0 0 0 0 ... (5 Replies)
Discussion started by: LMHmedchem
5 Replies
LEARN ABOUT XFREE86
regex
regex(1F) FMLI Commands regex(1F)NAME
regex - match patterns against a string
SYNOPSIS
regex [-e] [ -v "string"] [ pattern template] ... pattern [template]
DESCRIPTION
The regex command takes a string from the standard input, and a list of pattern / template pairs, and runs regex() to compare the string
against each pattern until there is a match. When a match occurs, regex writes the corresponding template to the standard output and
returns TRUE. The last (or only) pattern does not need a template. If that is the pattern that matches the string, the function simply
returns TRUE. If no match is found, regex returns FALSE.
The argument pattern is a regular expression of the form described in regex(). In most cases, pattern should be enclosed in single quotes
to turn off special meanings of characters. Note that only the final pattern in the list may lack a template.
The argument template may contain the strings $m0 through $m9, which will be expanded to the part of pattern enclosed in ( ... )$0 through
( ... )$9 constructs (see examples below). Note that if you use this feature, you must be sure to enclose template in single quotes so
that FMLI does not expand $m0 through $m9 at parse time. This feature gives regex much of the power of cut(1), paste(1), and grep(1), and
some of the capabilities of sed(1). If there is no template, the default is $m0$m1$m2$m3$m4$m5$m6$m7$m8$m9.
OPTIONS
The following options are supported:
-e Evaluates the corresponding template and writes the result to the standard output.
-v "string" Uses string instead of the standard input to match against patterns.
EXAMPLES
Example 1: Cutting letters out of a string
To cut the 4th through 8th letters out of a string (this example will output strin and return TRUE):
`regex -v "my string is nice" '^.{3}(.{5})$0' '$m0'`
Example 2: Validating input in a form
In a form, to validate input to field 5 as an integer:
valid=`regex -v "$F5" '^[0-9]+$'`
Example 3: Translating an environment variable in a form
In a form, to translate an environment variable which contains one of the numbers 1, 2, 3, 4, 5 to the letters a, b, c, d, e:
value=`regex -v "$VAR1" 1 a 2 b 3 c 4 d 5 e '.*' 'Error'`
Note the use of the pattern '.*' to mean "anything else".
Example 4: Using backquoted expressions
In the example below, all three lines constitute a single backquoted expression. This expression, by itself, could be put in a menu defini-
tion file. Since backquoted expressions are expanded as they are parsed, and output from a backquoted expression (the cat command, in this
example) becomes part of the definition file being parsed, this expression would read /etc/passwd and make a dynamic menu of all the login
ids on the system.
`cat /etc/passwd | regex '^([^:]*)$0.*$' '
name=$m0
action=`message "$m0 is a user"`'`
DIAGNOSTICS
If none of the patterns match, regex returns FALSE, otherwise TRUE.
NOTES
Patterns and templates must often be enclosed in single quotes to turn off the special meanings of characters. Especially if you use the
$m0 through $m9 variables in the template, since FMLI will expand the variables (usually to "") before regex even sees them.
Single characters in character classes (inside []) must be listed before character ranges, otherwise they will not be recognized. For exam-
ple, [a-zA-Z_/] will not find underscores (_) or slashes (/), but [_/a-zA-Z] will.
The regular expressions accepted by regcmp differ slightly from other utilities (that is, sed, grep, awk, ed, and so forth).
regex with the -e option forces subsequent commands to be ignored. In other words, if a backquoted statement appears as follows:
`regex -e ...; command1; command2`
command1 and command2 would never be executed. However, dividing the expression into two:
`regex -e ...``command1; command2`
would yield the desired result.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWcsu |
+-----------------------------+-----------------------------+
SEE ALSO awk(1), cut(1), grep(1), paste(1), sed(1), regcmp(3C), attributes(5)SunOS 5.10 12 Jul 1999 regex(1F)