1) I wrote a script and gave the desired permissions using "chmod 755 scriptname". Now if i edit the script file, why do i need to set the permission again? Didn't i set the permission attribute.. or if i edit the file, does the inode number of file changes?
2) I am running my unix on a server... (1 Reply)
I have 2 files; one file (say, details.txt) contains the details of employees and another file (say, emp.txt) has some selected employee names. I am extracting employee details from details.txt by using emp.txt and the corresponding code is:
while read line
do
emp_name=`echo $line`
grep -e... (7 Replies)
i'm trying to write a bash script that executes a mysql statement
mysql -sN -e INSERT INTO "$database"."$tableprefix"users (var1, var2,var3) VALUES (123, '1','')
i don't know where to put the quotes
it doesnt work with this one: `
it seems i can only put double quotes around the... (0 Replies)
I have set up a bash script to run a long list of things that I need to time. I would like to redirect the output of time to a file. I have set it up like,
echo "Runtimes for servlet 4, 100K structures" > test_times.txt
echo "" >> test_times.txt
echo "runs where N=10" >> test_times.txt
echo... (7 Replies)
We have a production file system which has 6+ million files with more than 1 tera byte in size. When trying to delete selective files through a weekly script files are not deleted.
Please advise with ideas. (5 Replies)
When I run the below bash I get the expected output, which is the sum of all matching targets less than 20 in $file1. The filename in the directory is fixed (in bold).
for file1 in /home/cmccabe/Desktop/test/panel/reads/16-0000_EPIL70.txt ; do
bname=`basename $file1`
... (3 Replies)
Hi All,
This query is regarding performance improvement of a command.
I have a list of IDs in a file (say file1 with single ID column) and file2 has the data rows.
I need to get the IDs from file1 and search in file2, matching rows from file2 should be written to a file3.
For this... (4 Replies)
Hello, I have a file in the following format
id sample platform R1 R2 gene1 gene2 gene3
1 abc llumina R1_001.fastq.gz R2_001.fastq.gz apoe prnpp asp
2 def llumina R1_001.fastq.gz R2_001.fastq.gz apoe prnpp
3 ghi llumina ... (3 Replies)
I need to find a file and print its contents
I am trying but it is not working
find -path /opt/app-root/src/.npm/_logs -type f -name "*.log" -print
Version
$ bash -version
GNU bash, version 4.4.12(1)-release (x86_64-pc-msys) (1 Reply)
I have multiple xml files where i want to update a subnode if the subnode project points to different project or insert a subnode if it doesn't exist using a xmlstarlet or any other command that can be used in a bash script.
I have been able to update the subnode project if it doesn't point to... (1 Reply)
Perl::Critic::Policy::InputOutput::ProhibitBacktickOperaUser(Contributed Perl DocumPerl::Critic::Policy::InputOutput::ProhibitBacktickOperators(3)NAME
Perl::Critic::Policy::InputOutput::ProhibitBacktickOperators - Discourage stuff like "@files = `ls $directory`".
AFFILIATION
This Policy is part of the core Perl::Critic distribution.
DESCRIPTION
Backticks are super-convenient, especially for CGI programs, but I find that they make a lot of noise by filling up STDERR with messages
when they fail. I think its better to use IPC::Open3 to trap all the output and let the application decide what to do with it.
use IPC::Open3 'open3';
$SIG{CHLD} = 'IGNORE';
@output = `some_command`; #not ok
my ($writer, $reader, $err);
open3($writer, $reader, $err, 'some_command'); #ok;
@output = <$reader>; #Output here
@errors = <$err>; #Errors here, instead of the console
CONFIGURATION
Alternatively, if you do want to use backticks, you can restrict checks to void contexts by adding the following to your .perlcriticrc
file:
[InputOutput::ProhibitBacktickOperators]
only_in_void_context = 1
The purpose of backticks is to capture the output of an external command. Use of them in a void context is likely a bug. If the output
isn't actually required, "system()" should be used. Otherwise assign the result to a variable.
`some_command`; #not ok
$output = `some_command`; #ok
@output = `some_command`; #ok
NOTES
This policy also prohibits the generalized form of backticks seen as "qx{}".
See perlipc for more discussion on using "wait()" instead of "$SIG{CHLD} = 'IGNORE'".
You might consider using the "capture()" function from the IPC::System::Simple module for a safer way of doing what backticks do,
especially on Windows. The module also has a safe wrapper around "system()".
AUTHOR
Jeffrey Ryan Thalhammer <jeff@imaginative-software.com>
COPYRIGHT
Copyright (c) 2005-2011 Imaginative Software Systems. All rights reserved.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. The full text of this license
can be found in the LICENSE file included with this module.
perl v5.16.3 2014-06-09 Perl::Critic::Policy::InputOutput::ProhibitBacktickOperators(3)