10 More Discussions You Might Find Interesting
1. UNIX for Dummies Questions & Answers
Hi,
I have a file that looks something like
>1-18*anc... (12 Replies)
Discussion started by: jyu429
12 Replies
2. Shell Programming and Scripting
Need Assistance in shell programming... I have a huge file which has multiple stations and i wanted to search particular station and extract few lines from it and the rest is not needed
Bold letters are the stations . The whole file has multiple stations .
Below example i wanted to search... (4 Replies)
Discussion started by: ajayram_arya
4 Replies
3. Shell Programming and Scripting
Hi,
I have a unix file with contents as below
Line1: ABC MNN X$$QWERTY$$ JKL
Line2: HELLO $$HOW$$ ARE $$YOU$$ DOING
i want to extract the string between $$ and $$ ie i want the output as QWERTY
HOW YOU
i want those strings seperated by some character say |
desired output is... (7 Replies)
Discussion started by: vinredmac
7 Replies
4. Shell Programming and Scripting
continuing from my previous post, whose link is given below as a reference
https://www.unix.com/shell-programming-scripting/171076-shell-scripting.html#post302573569
consider there is create table commands in a file for eg:
CREATE TABLE `Blahblahblah` (
`id` int(11) NOT NULL... (2 Replies)
Discussion started by: vivek d r
2 Replies
5. UNIX for Dummies Questions & Answers
Hi.
I have a log file which gets updated by a java process and it uses ASCII STX and ETX characters (i.e CTRL-B and CTRL-C characters) to demarcate each XML message logged.
so the format of the file is something like
STX XML_MESSAGE1
..
..
ETX STX XML_MESSAGE2
..
..
ETX
each XML... (4 Replies)
Discussion started by: gregoryp
4 Replies
6. Shell Programming and Scripting
Hi, guys. I have one question:
I need to search for a string in a file, and then extract another string from the file and assign it to a variable.
For example:
the contents of the file (group) is below:
...
ftp:x:23:
mail:x:34
...
testing:x:2001
sales:x:2002
development:x:2003
...... (6 Replies)
Discussion started by: daikeyang
6 Replies
7. Shell Programming and Scripting
Hi,
I am writing a Perl script that reads in many lines, if a line meets the criteria I want to edit, it. For example, the script will return the following example line... test=abc123
All I want to do is strip off the "test=" and just be left with the abc123. In my script I can easily... (3 Replies)
Discussion started by: edrichard
3 Replies
8. Shell Programming and Scripting
Hello everyone,
I'm writing a script to add a string to an XML file, right after a specified string that only occurs once in the file. For testing purposes I created a file 'testfile' that looks like this:
1
2
3
4
5
6
6
7
8
9
And this is the script as far as I've managed:
... (2 Replies)
Discussion started by: heliode
2 Replies
9. Shell Programming and Scripting
hi,
how to echo \\ in unix
ie echo the path
\\dir1\dir2\\dir3
thanks,
Sam (7 Replies)
Discussion started by: sam99
7 Replies
10. Shell Programming and Scripting
I have a string as follows
IS*blahblah
TED~blahblah
etc.
I want to list down only IS and TED
Can someone help me? (24 Replies)
Discussion started by: kumariak
24 Replies
expr(1B) SunOS/BSD Compatibility Package Commands expr(1B)
NAME
expr - evaluate arguments as a logical, arithmetic, or string expression
SYNOPSIS
/usr/ucb/expr argument...
DESCRIPTION
The expr utility evaluates expressions as specified by its arguments. After evaluation, the result is written on the standard output. Each
token of the expression is a separate argument, so terms of the expression must be separated by blanks. Characters special to the shell
must be escaped. Note: 0 is returned to indicate a zero value, rather than the null string. Strings containing blanks or other special
characters should be quoted. Integer-valued arguments may be preceded by a unary minus sign. Internally, integers are treated as 32-bit,
two's-complement numbers.
The operators and keywords are listed below. Characters that need to be escaped are preceded by `'. The list is in order of increasing
precedence, with equal precedence operators grouped within {} symbols.
expr | expr
Returns the evaluation of the first expr if it is neither NULL nor 0; otherwise, returns the evaluation of the second expr if it is not
NULL; otherwise, 0.
expr & expr
Returns the first expr if neither expr is NULL or 0, otherwise returns 0.
expr { =, , , <, <=, != } expr
Returns the result of an integer comparison if both arguments are integers, otherwise returns the result of a lexical comparison.
expr { +, - } expr
Addition or subtraction of integer-valued arguments.
expr { , /, % } expr
Multiplication, division, or remainder of the integer-valued arguments.
string : regular-expression
match string regular-expression
The two forms of the matching operator above are synonymous. The matching operators : and match compare the first argument with the
second argument which must be a regular expression. Regular expression syntax is the same as that of regexp(5), except that all pat-
terns are "anchored" (treated as if they begin with ^) and therefore ^ is not a special character, in that context. Normally, the
matching operator returns the number of characters matched (0 on failure). Alternatively, the ... pattern symbols can be used to
return a portion of the first argument.
substr string integer-1 integer-2
Extracts the substring of string starting at position integer-1 and of length integer-2 characters. If integer-1 has a value greater
than the length of string, expr returns a null string. If you try to extract more characters than there are in string, expr returns all
the remaining characters from string. Beware of using negative values for either integer-1 or integer-2 as expr tends to run forever
in these cases.
index string character-list
Reports the first position in string at which any one of the characters in character-list matches a character in string.
length string
Returns the length (that is, the number of characters) of string.
( expr )
Parentheses may be used for grouping.
EXAMPLES
Example 1: Adding an integer to a shell variable
Add 1 to the shell variable a.
a='expr $a + 1'
Example 2: Returning a path name segment
Return the last segment of a path name (that is, the filename part). Watch out for / alone as an argument: expr will take it as the divi-
sion operator (see BUGS below).
# 'For $a equal to either "/usr/abc/file" or just "file"'
expr $a : '.*/ $a
Example 3: Using // characters to simplify the expression
The addition of the // characters eliminates any ambiguity about the division operator and simplifies the whole expression.
# A better representation of example 2.
expr //$a : '.*/
Example 4: Returning the value of a variable
Returns the number of characters in $VAR.
expr $VAR : '.*'
EXIT STATUS
expr returns the following exit codes:
0 If the expression is neither NULL nor 0.
1 If the expression is NULL or 0.
2 For invalid expressions.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWscpu |
+-----------------------------+-----------------------------+
SEE ALSO
sh(1), test(1), attributes(5), regexp(5)
DIAGNOSTICS
syntax error for operator/operand errors
non-numeric argument if arithmetic is attempted on such a string
division by zero if an attempt to divide by zero is made
BUGS
After argument processing by the shell, expr cannot tell the difference between an operator and an operand except by the value. If $a is an
=, the command:
expr $a = '='
looks like:
expr = = =
as the arguments are passed to expr (and they will all be taken as the = operator). The following works:
expr X$a = X=
Note: the match, substr, length, and index operators cannot themselves be used as ordinary strings. That is, the expression:
example% expr index expurgatorious length
syntax error
example%
generates the `syntax error' message as shown instead of the value 1 as you might expect.
SunOS 5.10 6 Jun 2000 expr(1B)