Then let me continue with lession#2.
Within $( ) there is a parser problem with the old style case statements.
But bash4 and ksh93 have got a fix.
Bash is not standard on AIX. And many people I see using bash are using bash-4.2 not 4.4 - so when you say bash4 - do you mean any bash-4.X or are you talking about the X (again, most people just say bash - not bashX).
So, maybe - we should split this off - but please come up with a catchy "subject line" - as we are sort of "all over the place" - shells, POSIX, environments, ...
Can someone explain the difference between backticks and system when
evaluated in these if statements:
sub getDate {
print "start date\n";
if ( system("/bin/date") ) {
print "can't get date\n";
exit(2);
}
print "finish date\n";
}
Returns the following:
start date
Thu... (5 Replies)
Hi, I'm trying to do something like this: range= `expr `date '+%m'` - 1` and it does not work. How can I tell it to evaluate an expression within another expression evaluation? I was at first worried that `date '+%m'` would return a string but apparently expr does the math okay normally, so the... (3 Replies)
Hi,
I would like to change some lines in my mysql-dump, because there a syntax problems with some version of mysql.
I 'd like to change
USE ´someDatabase´;
to
USE someDatabase;
(without backticks) using the sed command in the shell
Thanks & best regards
Bernd (5 Replies)
I'm always concerned I might be abusing backticks within my scripts. A current script I'm writing has this for example:
stripscriptname=`echo $scriptname | sed 's/\(.*\)\..*/\1/'`
stripsearch=`echo $searchpattern | tr -d ' ,/'`
Both of these variables are set inside the script (in fact,... (2 Replies)
Hey all. Just a fast question, what is the technical difference between using back ticks and using xargs to perform a command?
Here's an example
Find /mydir -name *.conf |xargs rm
Vs
Rm 'find /mydir -name *.conf'
Is there a performance hit? I know they do the same thing but which is... (1 Reply)
Hi everyone. This is a bit of a perl/linux mixed question. I am trying to redirect STDOUT of chsh by using the following line of perl code.
system ("chsh -s /sbin/nologin $testing 1>/dev/null");
This should redirect STDOUT to /dev/null but it won't do that for some odd reason. Any ideas or... (6 Replies)
Input file:
'data_1'
'data_10'
'data1311'
'235data_13'
Desired output:
data_1
data_10
data1311
235data_13
Can I know how to remove back tick"'" in a file?
Many thanks for advice. (3 Replies)
I have been testing a new script and cannot figure out why my `cat spath` will not execute on the remote machine?
sudo ssh -p 22344 -o "PasswordAuthentication no" -o "HostbasedAuthentication yes" -l testuser 192.168.1.6 "find `cat spath` -depth"
cat: spath: No such file or directory
but... (0 Replies)
I'm trying to make a dialog window that prints the output of grep that takes the output of find. Unfortunately my nested backticks don't work.
Here is the dialog window:
dialog --stdout --title "test" --backtitle "test" --msgbox "Test:\n `grep -l "${tablica}" `find $string``" 16 60I think I... (2 Replies)
Discussion started by: Starting_Leaf
2 Replies
LEARN ABOUT OSF1
command
command(1) General Commands Manual command(1)NAME
command - Treats command arguments as simple commands
SYNOPSIS
command [-p] command_name [argument...]
command [-v | -V] command_name
The command command causes the shell to treat the arguments to command as simple commands, and suppresses the default shell function
lookup.
STANDARDS
Interfaces documented on this reference page conform to industry standards as follows:
command: XCU5.0
Refer to the standards(5) reference page for more information about industry standards and associated tags.
OPTIONS
Performs the command search using a default value for PATH that is guaranteed to find all of the standard utilities. Writes a string to
standard output that indicates the path name or command to be used by the shell in the current shell execution environment to invoke com-
mand_name. Writes a string to standard output that indicates how the name given in the command_name operand will be interpreted by the
shell in the current shell execution environment.
DESCRIPTION
The command command allows you to run the following commands: User-defined commands whose names correspond to shell built-in commands.
System commands whose names correspond to shell built-in commands.
The command_name argument specifies the name of a utility. The one or more optional arguments to command_name specify strings treated as
arguments to the specified utility. It also provides information concerning how a command name will be interpreted by the shell.
NOTES
[Tru64 UNIX] If command_name is not the name of a function, the effect of command is the same as would be obtained by specifying com-
mand_name without command.
RESTRICTIONS
Since the -v and -V options to command produce output in relation to the current shell execution environment, if command is called in a
subshell or separate utility execution environment, it may not produce correct results. The following are examples of this type of opera-
tion:
(PATH=foo command -v) nohup command -v
EXIT STATUS
When the -v or -V options are specified, command returns one of the following values. Successful completion. The command_name could not
be found, or an error occurred.
If the -v or -V options are not specified, command returns one of the following values on error. The utility specified by command_name was
found but could not be invoked. An error occurred in the command command, or the utility specified by the command_name argument could not
be invoked.
If no error occurs, the exit status of command is that of the command specified by the arguments to command.
EXAMPLES
To ensure execution of the simple command pwd instead of the pwd shell built-in command, enter the following: command -p pwd
The preceding command displays the full path name of the current directory, and does not perpetuate a view of the current directory loca-
tion created by links as the shell built-in command might do.
ENVIRONMENT VARIABLES
The following environment variables affect the execution of command: Provides a default value for the internationalization variables that
are unset or null. If LANG is unset or null, the corresponding value from the default locale is used. If any of the internationalization
variables contains an invalid setting, the utility behaves as if none of the variables had been defined. If set to a non-empty string
value, overrides the values of all the other internationalization variables. Determines the locale for the interpretation of sequences of
bytes of text data as characters (for example, single-byte as opposed to multibyte characters in arguments). Determines the locale that
should be used to affect the format and contents of diagnostic messages written to standard error. Determines the location of message cat-
alogues for the processing of LC_MESSAGES. Determines the search path used during the command search unless the -p option is specified.
SEE ALSO
Commands: env(1), hash(1), type(1)
Standards: standards(5)command(1)