10-13-2015
To check if a file is open and in use (logs are being written to it)
Hello Experts,
I need to write a shell script to check if a file is open and something is being written to it. I want to know how OS handles it. I checked with lsof command but it is not working. For a test I did this.
HTML Code:
while true; do echo `date` >>abc.txt; done
then I checked
lsof | grep -i /home/admin/abc.txt
It did not show any open process to me.
Yesterday when I tried the same thing, it once showed up i.e. I could see the output of
lsof command but then again it disappeared.
I also tried the same by opening a file through
vi but no luck.
I also want to know how system behaves for a file that is being open through vi, gedit etc and the one that is being appended through a loop or some script.
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LEARN ABOUT XFREE86
checkbashisms
CHECKBASHISMS(1) General Commands Manual CHECKBASHISMS(1)
NAME
checkbashisms - check for bashisms in /bin/sh scripts
SYNOPSIS
checkbashisms script ...
checkbashisms --help|--version
DESCRIPTION
checkbashisms, based on one of the checks from the lintian system, performs basic checks on /bin/sh shell scripts for the possible presence
of bashisms. It takes the names of the shell scripts on the command line, and outputs warnings if possible bashisms are detected.
Note that the definition of a bashism in this context roughly equates to "a shell feature that is not required to be supported by POSIX";
this means that some issues flagged may be permitted under optional sections of POSIX, such as XSI or User Portability.
In cases where POSIX and Debian Policy disagree, checkbashisms by default allows extensions permitted by Policy but may also provide
options for stricter checking.
OPTIONS
--help, -h
Show a summary of options.
--newline, -n
Check for "echo -n" usage (non POSIX but required by Debian Policy 10.4.)
--posix, -p
Check for issues which are non POSIX but required to be supported by Debian Policy 10.4 (implies -n).
--force, -f
Force each script to be checked, even if it would normally not be (for instance, it has a bash or non POSIX shell shebang or appears
to be a shell wrapper).
--extra, -x
Highlight lines which, whilst they do not contain bashisms, may be useful in determining whether a particular issue is a false posi-
tive which may be ignored. For example, the use of "$BASH_ENV" may be preceded by checking whether "$BASH" is set.
--version, -v
Show version and copyright information.
EXIT VALUES
The exit value will be 0 if no possible bashisms or other problems were detected. Otherwise it will be the sum of the following error val-
ues:
1 A possible bashism was detected.
2 A file was skipped for some reason, for example, because it was unreadable or not found. The warning message will give details.
SEE ALSO
lintian(1).
AUTHOR
checkbashisms was originally written as a shell script by Yann Dirson <dirson@debian.org> and rewritten in Perl with many more features by
Julian Gilbey <jdg@debian.org>.
DEBIAN
Debian Utilities CHECKBASHISMS(1)