That still doesn't explain the purpose behind this odd goal, which is what I was wondering, because there may be more straightforward ways to do it than the design you've chosen.
In sh, you can try eval "$cmd" to force it to re-evaluate the line again after the first expansion, which will indeed interpret the literal quotes as a string parameter.
This is dangerous however, because eval accepts all valid shell syntax, including backticks and variables. Someone could feed it a tailored string to extract variables from your program or run whatever commands they wanted.
Because of this you may wish to make the string into
to prevent $COMMENT from being expanded. eval will expand it for you, but won't interpret its contents as anything other than string. I don't think this is possible in C shell, only sh.
Last edited by Corona688; 06-21-2011 at 02:36 PM..
I am trying to strip all leading and trailing spaces of a shell variable using either awk or sed or any other utility, however unscuccessful and need your help.
echo $SH_VAR | command_line Syntax.
The SH_VAR contains embedded spaces which needs to be preserved. I need only for the leading and... (6 Replies)
Hello all
i need to pass to my shell script parameter that looks like "2 3 3"
inside the script i need to use this string that looks like this "2 3 3"
but when i try to print the script im getting syntax error , this is my script :
set s = $1
echo $s (1 Reply)
I am new to scripting and I needed to know if there would be an easy way to delete extra spaces in a text file. I have a file with three rows with 22 numbers each, but there is extra spaces between the numbers when it gets output by this program AFNI that I am using. What script would help delete... (2 Replies)
My shell is csh and it is required.
I have a file like sample.txt
------------------------
a b c
d
e
f
g h i
------------------------
I want set the file to a variable and print it out in the same format.
I have tried something like this, but not succed.
% cat ~/tmp/sample.txt
a b c
d... (8 Replies)
I have a simple script that sets a value and reads the value in csh:
set -x
set a = 10
echo $a
The output of the script does not show the value of a
+ set a = 10
+ echo
any help would be great. (4 Replies)
I am reading a number of files but then I want to put the ranges
xmin xmax ymin ymax
as arrays for each file.
Any idea how I can do this???
set j = 1
echo "Welcome $i times"
while ( $j <= $i )
echo "$j"
set fname = $fin-bst-misf.xy
echo " "$fname
... (0 Replies)
Hi, i have this text:
X (m) 4917536.9627 4917536.9673 0.0090 -0.0046
Y (m) -815726.1383 -815726.1294 0.0061 -0.0089
Z (m) 3965857.4730 3965857.4840 0.0071 -0.0110
X (m) 4917536.9627 4917537.1411 -0.1784 0.1710
Y (m) -815726.1383 -815726.4859 0.3476 0.3489
Z (m) 3965857.4730... (2 Replies)
Hello all. I am a newb obviously and a bit stumped on this, so any help gratefully accepted.
The script is extracting metadata from individual mp3 files, then (hopefully will be) sorting them into newly-created subdirectories. I have filtered out the relevant metadata and have the album names... (8 Replies)
Hello.
In csh if I declared a variable to be a set of arguments can I retrieve a particular element from that set.
My code
set files=(`ls`)
and I want to get only one file from $files. How can I do that????(It is just an abstract example):wall:
Thanks in advance :) (5 Replies)
Discussion started by: FUTURE_EINSTEIN
5 Replies
LEARN ABOUT MINIX
exec
exec(1) User Commands exec(1)NAME
exec, eval, source - shell built-in functions to execute other commands
SYNOPSIS
sh
exec [argument...]
eval [argument...]
csh
exec command
eval argument...
source [-h] name
ksh
*exec [arg...]
*eval [arg...]
DESCRIPTION
sh
The exec command specified by the arguments is executed in place of this shell without creating a new process. Input/output arguments may
appear and, if no other arguments are given, cause the shell input/output to be modified.
The arguments to the eval built-in are read as input to the shell and the resulting command(s) executed.
csh
exec executes command in place of the current shell, which terminates.
eval reads its arguments as input to the shell and executes the resulting command(s). This is usually used to execute commands generated as
the result of command or variable substitution.
source reads commands from name. source commands may be nested, but if they are nested too deeply the shell may run out of file descrip-
tors. An error in a sourced file at any level terminates all nested source commands.
-h Place commands from the file name on the history list without executing them.
ksh
With the exec built-in, if arg is given, the command specified by the arguments is executed in place of this shell without creating a new
process. Input/output arguments may appear and affect the current process. If no arguments are given the effect of this command is to mod-
ify file descriptors as prescribed by the input/output redirection list. In this case, any file descriptor numbers greater than 2 that are
opened with this mechanism are closed when invoking another program.
The arguments to eval are read as input to the shell and the resulting command(s) executed.
On this man page, ksh(1) commands that are preceded by one or two * (asterisks) are treated specially in the following ways:
1. Variable assignment lists preceding the command remain in effect when the command completes.
2. I/O redirections are processed after variable assignments.
3. Errors cause a script that contains them to abort.
4. Words, following a command preceded by ** that are in the format of a variable assignment, are expanded with the same rules as a vari-
able assignment. This means that tilde substitution is performed after the = sign and word splitting and file name generation are not
performed.
EXIT STATUS
For ksh:
If command is not found, the exit status is 127. If command is found, but is not an executable utility, the exit status is 126. If a redi-
rection error occurs, the shell exits with a value in the range 1-125. Otherwise, exec returns a zero exit status.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWcsu |
+-----------------------------+-----------------------------+
SEE ALSO csh(1), ksh(1), sh(1), attributes(5)SunOS 5.10 17 Jul 2002 exec(1)