No, it is not. A "variable" is something like "$name" or "${name}", where "name" is a name you choose. "$xyz" might be a variable, but "v$xyz" is a literal "v" followed by the content of a variable with the name "xyz".
Quote:
Originally Posted by green_k
the file name like v$xyz_xxxx_xxxx.txt.
OK, but is the "$xyz" in this filename now meant literally or should that signify the variable portion of the filename which you want to transport via the variable? If the first is the case a simple quotation will suffice, because this is what it is for - inside of (single) quotes the "$" loses its special meaning to the shell and reverts back to a normal character:
will first replace "$xyz_xxxx_xxxx" with the content of a variable named "xyz_xxxx_xxxx" (which most probably will not exist so that it evaluates to "", the empty string) and therefore search for a file named "v.txt". Whereas:
(notice the single quotes) will look for a file named exactly this: "v$xyz_xxxx_xxxx.txt".
If "$xyz" is a variable and you want to use that as the changing part of an otherwise fixed filename then this code snippet is for you:
This will search for a file name "vsome$thing_xxxx_xxxx.txt". Because of the braces around "xyz" the shell knows that only this (and not the rest of the string) is the name of the variable. Notice the double quotes: you should habitually double-quote every use of any variable - ever and always! (There are only very few exceptions to this rule of thumb.) This way blanks (yes, filename can contain blanks) will not break your script.
hey there
im a bit stuck on executing commands that include the special character '?'. can someone recommend a way on how i would be able to execute it?? i thought the glob function could be useful (still mite be) but upon entering the command
'ls pars?' it listed all the files in the... (1 Reply)
Hi ,
I am doing invert grep using -v but the string contain "/" which break the grep command and it do not skip the lines with "/" on it.
Diffu.txt
========
1159c1159
< <td align="right" valign="middle" class="paddingRight2px" id="featureListItemChannelButton7466">
---
> <td... (1 Reply)
Hi,
I am trying to unload file from a database. Which contains few lines with the character below. Rest of the data was unloaded appropriately.
a) What does this below character means?
b) How can i remove it,
I already have sed '/^$/d'
c) Will this effect the file by any means... (4 Replies)
Hi,
In the shell script, i need to remove the special charater "\" with "\\". For example, i need to replace "D:\FXT\ABC.TXT" with "D:\\FXT\\ABC.TXT".
However, when trying to do something like , i get the below error :-
-->echo "D:\FXT\ABC.TXT" | sed -e 's#\#\\#g'
sed: 0602-404 Function... (7 Replies)
I have below line in a unix file, I want to delete one character after "Â".
20091020.Non-Agency CMO Daily Trade Recap Â~V Hybrids
The result should be :
20091020.Non-Agency CMO Daily Trade Recap  Hybrids
i dont want to use "~V" anywhere in the sed command or any other command, just remove... (1 Reply)
I'm having issue capturing a value from file.list with a multiple spaces in a variable $i, tried various options like using double quotes, no quotes, single quotes, curly braces but to no avail.
cat file.list
aaa test bbb
ccc test ddd
eee test fff
for i in `cat file.list`
do
echo "$i";... (2 Replies)
Hi ,
I have input file like below
Hi this is "vinoth".
Hi happy to work with 'unix'
USA(united states of America)
My script variables are below :
Dquote=Ộ
Squote=&#$567
Obrac=&^986
Cbrac=&^745
I want to read the variables in my SED command to replace the double quote,single... (9 Replies)
When editing a file, vi displays a special character as ^L. Can you tell me the escaped character to be used in awk? And can that escaped character be used in a regexp in both sed and awk? (7 Replies)
Hello Folks,
Need to bisect strings based on a subset.
Below works good.
echo /a/b/c/d | awk -F"/c/d$" '{print $1}'
/a/b
However, it goes awry with special characters.
echo /a/b/c+/d | awk -F"/c+/d$" '{print $1}'
/a/b/c+/d
Desired output:
/a/b
Escaping the special characters... (11 Replies)
Hi,
on ksh
What does the following do?
grep -v "toolbox" $home_oracle/.profile >$home_oracle/.profile.$$ Thanks.
Please use CODE tags as required by forum rules! (3 Replies)
Discussion started by: big123456
3 Replies
LEARN ABOUT SUNOS
read
read(1) User Commands read(1)NAME
read - read a line from standard input
SYNOPSIS
/usr/bin/read [-r] var...
sh
read name...
csh
set variable = $<
ksh
read [ -prsu [n]] [ name ? prompt] [name...]
DESCRIPTION
/usr/bin/read
The read utility will read a single line from standard input.
By default, unless the -r option is specified, backslash () acts as an escape character. If standard input is a terminal device and the
invoking shell is interactive, read will prompt for a continuation line when:
o The shell reads an input line ending with a backslash, unless the -r option is specified.
o A here-document is not terminated after a NEWLINE character is entered.
The line will be split into fields as in the shell. The first field will be assigned to the first variable var, the second field to the
second variable var, and so forth. If there are fewer var operands specified than there are fields, the leftover fields and their interven-
ing separators will be assigned to the last var. If there are fewer fields than vars, the remaining vars will be set to empty strings.
The setting of variables specified by the var operands will affect the current shell execution environment. If it is called in a subshell
or separate utility execution environment, such as one of the following:
(read foo)
nohup read ...
find . -exec read ... ;
it will not affect the shell variables in the caller's environment.
The standard input must be a text file.
sh
One line is read from the standard input and, using the internal field separator, IFS (normally space or tab), to delimit word boundaries,
the first word is assigned to the first name, the second word to the second name, and so on, with leftover words assigned to the last name.
Lines can be continued using
ewline. Characters other than NEWLINE can be quoted by preceding them with a backslash. These backslashes
are removed before words are assigned to names, and no interpretation is done on the character that follows the backslash. The return code
is 0, unless an end-of-file is encountered.
csh
The notation:
set variable = $<
loads one line of standard input as the value for variable. (See csh(1)).
ksh
The shell input mechanism. One line is read and is broken up into fields using the characters in IFS as separators. The escape character,
(), is used to remove any special meaning for the next character and for line continuation. In raw mode, -r, the character is not
treated specially. The first field is assigned to the first name, the second field to the second name, and so on, with leftover fields
assigned to the last name. The -p option causes the input line to be taken from the input pipe of a process spawned by the shell using |&.
If the -s flag is present, the input will be saved as a command in the history file. The flag -u can be used to specify a one digit file
descriptor unit n to read from. The file descriptor can be opened with the exec special command. The default value of n is 0. If name is
omitted, REPLY is used as the default name. The exit status is 0 unless the input file is not open for reading or an end-of-file is encoun-
tered. An end-of-file with the -p option causes cleanup for this process so that another can be spawned. If the first argument contains a
?, the remainder of this word is used as a prompt on standard error when the shell is interactive. The exit status is 0 unless an end-of-
file is encountered.
OPTIONS
The following option is supported:
-r Does not treat a backslash character in any special way. Considers each backslash to be part of the input line.
OPERANDS
The following operand is supported:
var The name of an existing or non-existing shell variable.
EXAMPLES
Example 1: An example of the read command
The following example for /usr/bin/read prints a file with the first field of each line moved to the end of the line:
example% while read -r xx yy
do
printf "%s %s
" "$yy" "$xx"
done < input_file
ENVIRONMENT VARIABLES
See environ(5) for descriptions of the following environment variables that affect the execution of read: LANG, LC_ALL, LC_CTYPE, LC_MES-
SAGES, and NLSPATH.
IFS Determines the internal field separators used to delimit fields.
PS2 Provides the prompt string that an interactive shell will write to standard error when a line ending with a backslash is read and
the -r option was not specified, or if a here-document is not terminated after a newline character is entered.
EXIT STATUS
The following exit values are returned:
0 Successful completion.
>0 End-of-file was detected or an error occurred.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWcsu |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
SEE ALSO csh(1), ksh(1), line(1), set(1), sh(1), attributes(5), environ(5), standards(5)SunOS 5.10 28 Mar 1995 read(1)