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Full Discussion: check file exist before execution
Top Forums Shell Programming and Scripting check file exist before execution Post 302630047 by neutronscott on Wednesday 25th of April 2012 10:10:29 AM
Old 04-25-2012
Quote:
Originally Posted by guddu_12
Hi Robin

How to use error code and message generated by ls, can you please give me an example

Did you try my code with [ -e "$file" ] || exit 0 yet? I do believe this is a much better approach. There are pitfalls to parsing ls. ls produces a list for humans to read. The shell can already produce a working set of files with globbing. For example, files with spaces, and even directories:

Code:
$ touch 'file with spaces.log'
$ mkdir 'directory.log'; touch 'directory.log/file1' 'directory.log/file2'
$ for file in *.log; do echo "$file"; done
directory.log
file with spaces.log
$ for file in `ls -1 *.log`; do echo "$file"; done
file
with
spaces.log
directory.log:
file1
file2

You see that ls is not good for parsing. It's likely you can be certain your directory will not have files with spaces, nor directories with .LOG ending, but it's good practice. So I suggest simply adding a test inside the loop. This should do as well:

Code:
for log in *.LOG
do
    [ -f "$log" ] || continue
    load
    move
done

Last edited by neutronscott; 04-25-2012 at 11:12 AM.. Reason: code indentation
 

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LEARN ABOUT MOJAVE

nislog

nislog(1M)						  System Administration Commands						nislog(1M)

NAME

       nislog - display the contents of the NIS+ transaction log

SYNOPSIS

       /usr/sbin/nislog [-h num | -t num]  [-v] [directory...]

DESCRIPTION

       nislog  displays  the  contents of the NIS+ server transaction log on the standard output. This command can be used to track changes in the
       namespace. The /var/nis/trans.log file contains the transaction log maintained by the NIS+ server. When updates occur, they are	logged	to
       this  file  and	then  propagated  to replicas as log transactions.  When the log is checkpointed, updates that have been propagated to the
       replicas are removed.

       The nislog command can only be run on an NIS+ server by superuser. It displays the log entries for that server only.

       If directory is not specified, the entire log is searched. Otherwise, only those logs entries that correspond to the specified  directories
       are displayed.

OPTIONS

       -h num	       Display num transactions from the ``head'' of the log. If the numeric parameter is  0, only the log header is displayed.

       -t num	       Display	num transactions from the ``tail'' of the log. If the numeric parameter is  0, only the log header is displayed.

       -v	       Verbose mode.

FILES

       /var/nis/trans.log      transaction log

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWnisu			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       nis+(1), rpc.nisd(1M), nisfiles(4), attributes(5)

NOTES

       NIS+  might  not  be  supported in future releases of the SolarisTM Operating Environment. Tools to aid the migration from NIS+ to LDAP are
       available in the Solaris 9 operating environment. For more information, visit http://www.sun.com/directory/nisplus/transition.html.

SunOS 5.10							    12 Dec 2001 							nislog(1M)
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