Try with: `xargs --show-limits &lt;/dev/null`

    Your environment variables take up 2446 bytes
    POSIX upper limit on argument length (this system): 2092658
    POSIX smallest allowable upper limit on argument length (all systems): 4096
    Maximum length of command we could actually use: 2090212
    Size of command buffer we are actually using: 131072

There is no limit per argument, but a total for the whole command line length. In my system (Fedora 15/zsh) its closer to 2Mb. (line 4).

I came across &quot;How long an argument list your kernel can take on the command line before it chokes?&quot;:

    getconf ARG_MAX

which gives the following on my system:

    131072


e.g. 

    &lt;div class=&quot;big
                left
                important&quot;&gt; some content &lt;/div&gt;

Does anyone know if this breaks things / has good browser support?

Is it possible to have attribute values that span multiple lines?

I am attempting to do the equivalent of  

    if ( object1.class == object2.class )
    {
        //do something
    }  

which of course doesn&#39;t work, what method am I overlooking?


Determine if two Java objects are of the same class

I am calling SQL*Plus from Linux C Shell:

`sqlplus username/password @file.sql var1 var2 var3`

**If I pass a string as `var1`, how long can this string be?** 

Is it governed by the OS? In this case:

`Linux version 2.6.9-100.ELsmp (mockbuild@x86-010.build.bos.redhat.com) (gcc version 3.4.6 20060404 (Red Hat 3.4.6-11)) #1 SMP Tue Feb 1 12:17:32 EST 2011`

**Update:** Empirical testing yielded the following results:

 - A command line argument of 5200 characters gave the error, &quot;Word too long.&quot;
 - 1300 characters then produced the SQL*Plus error, &quot;string beginning &quot;(000796384...&quot; is too long. maximum size is 239 characters.&quot;
 - As soon as I got under 239 chars all was well.

I think I&#39;ll use `sqlldr` to overcome this.

Maximum length of command line argument that can be passed to SQL*Plus?

I am calling SQL*Plus from Linux C Shell:
<code>sqlplus username/password @file.sql var1 var2 var3</code>
If I pass a string as <code>var1</code>, how long can this string be?
Is it governed by the OS? In this case:
<code>Linux version 2.6.9-100.ELsmp (mockbuild@x86-010.build.bos.redhat.com) (gcc version 3.4.6 20060404 (Red Hat 3.4.6-11)) #1 SMP Tue Feb 1 12:17:32 EST 2011</code>
Update: Empirical testing yielded the following results:
<ul>
<li>A command line argument of 5200 characters gave the error, "Word too long."</li>
<li>1300 characters then produced the SQL*Plus error, "string beginning "(000796384..." is too long. maximum size is 239 characters."</li>
<li>As soon as I got under 239 chars all was well.</li>
</ul>
I think I'll use <code>sqlldr</code> to overcome this.

I want to mask my password while writing it with `*`.
I use Linux GCC for this code.
I know one solution is to use `getch()` function like this

    #include &lt;conio.h&gt;   
    int main()
    {
        char c,password[10];
        int i;
        while( (c=getch())!= &#39;\n&#39;);{
            password[i] = c;
            printf(&quot;*&quot;);
            i++;
        }
        return 1;
    }

but the problem is that `GCC` does not include `conio.h` file so, `getch()` is useless for me.
Does anyone have a solution?


Hide password input on terminal

Before installing [gnuplot][1], I set the environment variable `GNUPLOT_DRIVER_DIR = /home/gnuplot/build/src`. During the installation, something went wrong.

I want to remove the `GNUPLOT_DRIVER_DIR` environment variable. How can I achieve it?

  [1]: https://en.wikipedia.org/wiki/Gnuplot


How do I delete an exported environment variable?

I have a python program that creates temporary directories under `/temp` by using `tempfile.mkdtemp`. Unfortunately, the Python program did not delete the directory after using it. So now the disk space is low.

Questions:

1. How do I delete the temporary directories left under `/temp` manually? I tried to delete them manually but got &quot;permission denied&quot; error.
2. In the Python program, how to delete `temp` directory after using them?

How to delete a directory created with tempfile.mkdtemp?

I was trying to adjust initial heap size of a tomcat 7 (CentOS, java -version: 1.6.0_25-b06) instance by adding the following line to catalina.sh:

    export CATALINA_OPTS=&quot;-Xms=512M -Xmx=1024M&quot;

Starting up tomcat fails and logs the following message to catalina.out:

    Invalid initial heap size: -Xms=512m
    Could not create the Java virtual machine.

What is wrong with these options?

Tomcat 7: How to set initial heap size correctly?

This does not generate any output. How come?

    $ echo &#39;this 1 2 3&#39; | grep &#39;\d\+&#39;

But these do:

    $ echo &#39;this 1 2 3&#39; | grep &#39;\s\+&#39;
    this 1 2 3
    
    $ echo &#39;this 1 2 3&#39; | grep &#39;\w\+&#39;
    this 1 2 3


Is \d not supported by grep&#39;s basic expressions?

In `pom.xml` I have declaration like this

&lt;!-- language: xml --&gt;

        &lt;plugin&gt;
            &lt;groupId&gt;org.apache.maven.plugins&lt;/groupId&gt;
            &lt;artifactId&gt;maven-javadoc-plugin&lt;/artifactId&gt;
            &lt;executions&gt;
                &lt;execution&gt;
                    &lt;id&gt;attach-javadocs&lt;/id&gt;
                    &lt;goals&gt;
                        &lt;goal&gt;jar&lt;/goal&gt;
                    &lt;/goals&gt;
                &lt;/execution&gt;
            &lt;/executions&gt;
        &lt;/plugin&gt;

is there any way to turn that off from command line?

I do know I can extract that into a profile, but that is not what I want.

How can I disable the Maven Javadoc plugin from the command line?

I need help with `getopts`.

I created a Bash script which looks like this when run:

$ foo.sh -i env -d directory -s subdirectory -f file

It works correctly when handling one argument from each flag.  But when I invoke several arguments from each flag I am not sure how to pull the multiple variable information out of the variables in `getopts`.

    while getopts &quot;:i:d:s:f:&quot; opt
       do
         case $opt in
            i ) initial=$OPTARG;;
            d ) dir=$OPTARG;;
            s ) sub=$OPTARG;;
            f ) files=$OPTARG;;
        
         esac
    done

After grabbing the options I then want to build directory structures from the variables

    foo.sh -i test -d directory -s subdirectory -s subdirectory2 -f file1 file2 file3

Then the directory structure would be

    /test/directory/subdirectory/file1
    /test/directory/subdirectory/file2
    /test/directory/subdirectory/file3
    /test/directory/subdirectory2/file1
    /test/directory/subdirectory2/file2
    /test/directory/subdirectory2/file3

Any ideas?

Retrieving multiple arguments for a single option using getopts in Bash

I have this binary file on my Linux system...

     udit@udit-Dabba ~ $ cat file.enc
     Salted__s�bO��&lt;0�F���Jw!���]�:`C�LKȆ�l

Using the hexdump command, I see its information like this:

     udit@udit-Dabba ~ $ hexdump -C file.enc
     00000000  53 61 6c 74 65 64 5f 5f  1b 73 a1 62 4f 15 be f6  |Salted__.s.bO...|
     00000010  3c 30 cc 46 ee 10 13 11  84 bf 4a 77 21 a4 84 99  |&lt;0.F......Jw!...|
     00000020  0e 5d ef 11 18 3a 60 43  a0 4c 4b 1e c8 86 e6 6c  |.]...:`C.LK....l|
     00000030

Now I am given a file on some other system whose contents are like this:

     53 61 6c 74 65 64 5f 5f  1b 73 a1 62 4f 15 be f6
     3c 30 cc 46 ee 10 13 11  84 bf 4a 77 21 a4 84 99
     0e 5d ef 11 18 3a 60 43  a0 4c 4b 1e c8 86 e6 6c

And I need to find out that same exact binary information from this hexdump.

How can I proceed for that?

If there isn&#39;t any switch for that then C code will also work fine.

(But a Linux command with some switch is preferable)

**Limitation:**

The binary information in the file is output of an encryption algorithm, so contents should exactly match...






Transform hexadecimal information to binary using a Linux command

    parser.add_argument(&#39;-auto&#39;, action=&#39;store_true&#39;)

How can I store false if `-auto` is unspecified? I can faintly remember that this way, it stores None if unspecified



argparse store false if unspecified

How do I add an optional flag to my command line args?

eg. so I can write 

    python myprog.py 

or

    python myprog.py -w

I tried 

    parser.add_argument(&#39;-w&#39;)

But I just get an error message saying 

    Usage [-w W]
    error: argument -w: expected one argument

which I take it means that it wants an argument value for the -w option. What&#39;s the way of just accepting a flag? 

I&#39;m finding http://docs.python.org/library/argparse.html rather opaque on this question.




Python argparse command line flags without arguments

I have some queries to find out the ddl of some objects from a schema.
The result columns I am getting are truncated in the middle of the queries.

How can I increase the width of the column?

I tried with 

    SET SERVEROUTPUT ON SIZE 1000000;
    SET LINESIZE 50000;
    set pagesize 50000;
    set long 50000;

But I&#39;m still getting the same result.

how to increase sqlplus column output length?

How can I stop a running SELECT statement by killing the session?

The command is continuously giving me output based on the SELECT statement, I want to stop it in between.

How to kill a running SELECT statement

When executing the following code, it just says the procedure is completed and doesn&#39;t print the infomation i want it to (firstName, lastName) and then the other values from the select query in a table below.

     CREATE OR REPLACE PROCEDURE PRINT_ACTOR_QUOTES (id_actor char)
    AS
    CURSOR quote_recs IS
    SELECT a.firstName,a.lastName, m.title, m.year, r.roleName ,q.quotechar from quote q, role r,   
    rolequote rq, actor a, movie m
    where
    rq.quoteID = q.quoteID
    AND
    rq.roleID = r.roleID
     AND
    r.actorID = a.actorID
    AND
    r.movieID = m.movieID
    AND
     a.actorID = id_actor;
    BEGIN
    FOR row IN quote_recs LOOP
    DBMS_OUTPUT.PUT_LINE(&#39;a.firstName&#39; || &#39;a.lastName&#39;);

    end loop;
    END PRINT_ACTOR_QUOTES;
    / 
When setting server output on, I get 

    a.firstNamea.lastName
    a.firstNamea.lastName
    a.firstNamea.lastName
    a.firstNamea.lastName
multiple times!

DBMS_OUTPUT.PUT_LINE not printing

We have an application running locally where we&#39;re experiencing the following error:

&gt; ORA-12514: TNS:listener does not currently know of service requested
&gt; in connect descriptor

I&#39;ve tested the connection using `TNSPing` which resolved correctly and
I tried `SQLPlus` to try connecting, which failed with the same error as above. I used this syntax for `SQLPlus`:

    sqlplus username/password@addressname[or host name]

We have verified that:

- the TNS Listener on the server is running. 
- Oracle itself on the server is running. 

We don&#39;t know of any changes that were made to this environment. 
Anything else we can test?

ORA-12514 TNS:listener does not currently know of service requested in connect descriptor

   
I am trying to query a certain row by name in my sql database and it has an ampersand. I tried to set an escape character and then escape the ampersand, but for some reason this isn&#39;t working and I&#39;m uncertain as to what exactly my problem is.
 

    Set escape &#39;\&#39;
        select * from V1144engine.T_nodes where node_id in(
        select node2_id from V1144engine.T_edges where node1_id in(
        select node2_id from V1144engine.T_edges where node1_id in(
        select node2_id from V1144engine.T_edges where node1_id = 
          (select node_id from V1144engine.T_nodes where node_name = &#39;Geometric Vectors \&amp; Matrices&#39;)))
        and edge_type_id = 1)
        and node_type_id = 1
        and node_id in (
        select node2_id from V1144engine.T_edges where node1_id =
          (select node_id from V1144engine.T_nodes where node_name = &#39;Algebra II&#39;)
        and edge_type_id = 2);

Although this has a similar solution to [this question][1], the problems are posed very differently. They may end up having the same solution, but that does not mean that the questions are the same.


  [1]: https://stackoverflow.com/questions/118190/how-do-i-ignore-ampersands-in-a-sql-script-running-from-sql-plus

Escaping ampersand character in SQL string

I have a csh script (although I can change languages if it has any relevance) where I have to:

    sed s/AAA/BBB/ file

The problem is that AAA and BBB are paths, and so contain &#39;/&#39;. AAA is fixed, so I can say:

    sed s/\\\/A\\\/A\\\A/BBB/ file

However, BBB is based on variables, including $PWD. How do I escape the &#39;/&#39; in $PWD?

OR is there some other way I should be doing this entirely?

How to replace a path with another path in sed?

When I run the following command in `csh`, I got nothing, but it works in `bash`.
Is there any equivalent in `csh` which can redirect the standard error to standard out?

    somecommand 2&gt;&amp;1

Content Type	Original Author	Original Content on Stackoverflow
Question	Umber Ferrule	View Question on Stackoverflow
Solution 1 - Linux	Pablo Castellazzi	View Answer on Stackoverflow
Solution 2 - Linux	Umber Ferrule	View Answer on Stackoverflow

Maximum length of command line argument that can be passed to SQL*Plus?

Linux Problem Overview

Linux Solutions

Solution 1 - Linux

Solution 2 - Linux

Determine if two Java objects are of the same class

Is it possible to have attribute values that span multiple lines?

Attributions