Bash is the Bourne Again SHell, the successor to the classic Unix sh (shell).

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How to prevent malicious injection in argument to php “exec” (webhook -> bash script) [migrated]

I've written a webhook to integrate into chat (slack / mattermost api). The simplest way to get it up and running was a quick php script, which looks like this: <?php $token = $_POST["token"]; ...
-2
votes
1answer
42 views

SAVE IP ROUTE RULES AFTER REBOOT

I have two internet connections from two different ISPs and I need to balance & failover the traffic originating to and from my network between the two ISPs. My settings: FIRST ISP (eth0): ...
1
vote
2answers
30 views

How to run ./configure from a different folder?

I'm writing an ansible playbook which is supposed to compile from source some tool and install it. While checking my playbook, I've tried running the relevant commands manually to check their output. ...
2
votes
1answer
35 views

unix utility to limit the number of bytes placed into a bash variable

Is there a unix/linux utility, perhaps a shell builtin or an external command, that will limit the number of bytes placed into a bash variable? For example, I want to make sure STRING gets at most ...
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2answers
292 views

Rewrite sh script for freebsd

I have an sh script: #!/bin/bash fullpath="$1" filename="${fullpath##*/}" dir="${fullpath:0:${#fullpath} - ${#filename}}" base="${filename%.[^.]*}" ext="${filename:${#base} + 1}" if [ -f ...
2
votes
6answers
8k views

Don't need the whole line, just the match from regular expression

I simply need to get the match from a regular expression: $ cat myfile.txt | SOMETHING_HERE "/(\w).+/" The output has to be only what was matched, inside the parenthesis. Don't think I can use ...
23
votes
4answers
14k views

How can I check in bash if a shell is running in interactive mode?

How can I tell (in ~/.bashrc) if I'm running in interactive mode, or, say, executing a command over ssh. I want to avoid printing of ANSI escape sequences in .bashrc if it's the latter.
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votes
2answers
84 views

Allowing PHP to run specific bash script with root permissions

I have a php script calling a bash script like this: <?php $result = exec('sudo /bin/bash /var/www/my_bash_script.sh /var/www/vhosts/testsite/htdocs/'); var_dump($result); ?> This is ...
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7answers
28k views

Log all commands run by admins on production servers

It is company policy for admins to login to the servers via a personal username, and then run sudo -i to become root. Upon running sudo -i, sudo will create an environmental variable called ...
1
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0answers
16 views

Why my profile looks for /usr/local/etc/profile.global (NIS)

My Ubuntu ID is manged by NIS/yellowpage. For some reason, when I log in, I'm getting this message. cat@local:~$ ssh catserver cat@catserver's password: Welcome to Ubuntu 15.10 (GNU/Linux ...
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2answers
56 views

pacemaker corosynce lsb resource script( Sybase Database ASE Server and Backup Server)

I'm trying to create a lsb resource with pcs on rhel7.2 The "sybase" script is about Sybase Database ASE Server and Backup Server Startup & Stop & Restart $ status script Before ...
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2answers
3k views

Will Ansible prevent the execution of 'rm -rf /' in a shell script

This is based upon this hoax question here. The problem described is having a bash script which contains something to the effect of: rm -rf {pattern1}/{pattern2} ...which if both patterns include ...
8
votes
4answers
6k views

Possible to disable “You have new mail in /var/mail/root”?

I would like to disable the mailcheck in FreeBSD 9.1. My login shell is BASH, so I have tried to add unset MAILCHECK in /root/.bashrc and /root/.profile, but I still get those messages. Question ...
2
votes
2answers
23 views

how to match a whitespace in a bash variable

According to the man page, the string to the right of =~ is treated as an extended regular expression. I've tried the following things to match an "ok" surrounded by whitespace on either side, but ...
17
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5answers
14k views

Newline-separated xargs

Is it possible to make xargs use only newline as separator? (in bash on Linux and OS X if that matters) I know -0 can be used, but it's PITA as not every command supports NUL-delimited output.
71
votes
6answers
70k views

How to run a command multiple times?

Is there a way to run a command (e.g. ps aux|grep someprocess) for n times? Something like: run -n 10 'ps aux|grep someprocess' I want to use it interactively, please do not post scripts. ...
59
votes
4answers
16k views

Is there a difference between how two ampersands and a semi-colon operate in bash?

If I wanted to run two separate commands on one line, I could do this: cd /home; ls -al or this: cd /home && ls -al And I get the same results. However, what is going on in the ...
5
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2answers
134 views

Cat, Grep, Redirect Output… Blank File?

I just ran cat /opt/webapplications/Word/readme.log | grep -v 'Apple' and I got the output on the cli that I was expecting, which was all the lines in readme.log that did not contain 'Apple'... ...
1
vote
1answer
281 views

lftp mirror leaves empty folders on remote

My script is set up with this for lftp lftp -p 2218 -u $login,$pass sftp://$host << EOF set mirror:use-pget-n 5 mirror -c -P5 --depth-first --Remove-source-files ...
2
votes
2answers
206 views

Allowing httpd to run a bash script in /usr/bin/

Migrating a system from CentOS6 to RHEL7 with SELinux running Enforced. A php script makes a call to /usr/bin/processdata.sh to generate some data behind the scenes. This worked fine with the old ...
3
votes
4answers
1k views

Extract repository name from GitHub url in bash

Given ANY GitHub repository url string like: git://github.com/some-user/my-repo.git or git@github.com:some-user/my-repo.git or https://github.com/some-user/my-repo.git What is the best way in ...
6
votes
4answers
15k views

How do I rename multiple files by removing characters in bash?

I have to rename multiple files in directory by removing first 5 characters for each filename. How can I do this i bash/shell? I'm using Ubuntu 11.10. Thanks.
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6answers
195 views

Sed regexp /d deleting whole file

Given a typical known_hosts file: [123.45.67.89]:22 ssh-rsa bbuivvhbkbjdnflksndkfnksnfk... [98.76.54.32]:14444 ssh-rsa hohdibsodbfoasbfbsabdfbsd... [77.34.122.33]:32209 ssh-rsa ...
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11answers
11k views

Linux: How to use a file as input and output at the same time?

I've just run the following in bash: uniq .bash_history > .bash_history and my history file ended up completely empty. I guess I need a way to read the whole file before writing to it. How is ...
16
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5answers
51k views

Determine if filesystem or partition is mounted RO or RW via Bash Script?

Is there an easy way to determine if a mounted filesystem is mounted as Read-Only or Read-Write? I was thinking just to pipe mount but I thought there might be an easier way.
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votes
5answers
4k views

Send message to IRC channel from bash

I have installed ircd-hybrid on my Ubuntu Server (192.168.1.2, example.com). We use #teamchannel to communicate inside the team. The question is: how can I send some short message from example.com to ...
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votes
3answers
4k views

Linux file copy with ETA?

I'm copying a large amount of files between disks. There's approximately 16 GB of data. I'd like to see progress information, and even an estimated time of completion from the command line. Any ...
0
votes
0answers
23 views

Cacti poller runs but not full script

I'm using Cacti and the poller calls a bash script to get some data. At the end of this script I have a logical test and then an email is sent if true. The issue I have is when the poller is running ...
0
votes
0answers
22 views

“-bash: fork: retry: …” on SSH connection

When I'm connecting via ssh to my useraccount of my server, I'm getting the following error: -bash: fork: retry: No child processes -bash: fork: Resource temporarily unavailable Does anyone ...
0
votes
3answers
53 views

Bash if condition to check if a ubuntu package needs an upgrade?

I need a bash line to check if a ubuntu package needs an upgrade or not. For example, I want to check if the package 'firefox' needs an upgrade using dpkg or apt-get commands. Hypthetical Example: ...
8
votes
5answers
10k views

chsh: PAM authentication failed

i want to change default shell env and run chsh -s /bin/zsh as root user, but a error message appeared: chsh: PAM authentication failed. i find this thread ...
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6answers
2k views

How to set up “vi” shell environment as default

I'd like to use vi (set -o vi can do the trick) as default in my shell instead of emacs, but I do not want to put it into bash startup scripts. Why? Because I work as verification engineer and I am ...
0
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2answers
172 views

Unable to run a python3 script in CentOs7 [with python2.7] via cronjob

I have been trying to deal with this strage problem all morning. I have a simple crawler.py file, which contans a code that can only run under python3 to be exact under python3.3 evenrionment Now, ...
2
votes
2answers
53 views

printing user of subshell obtaining root via su -

Can I print the username which is obtaining root access via su - on the root console upon obtaining root? user1$ su - password: obtained root via user1 #
2
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3answers
1k views

Apache 500 Error When Using Symlinks

Here is an excerpt of the deployment script I use to deploy php apps on my CentOS server. echo "Starting Deployment to $SITE_FOLDER (Relase Directory: $RELEASE_DIR)..." svn --username=$SVN_USER ...
3
votes
5answers
1k views

Pass your password to your SSH key via a script

I am writing a script that will allow me to retrieve a file from all of my servers at once. I have SSH keys in place in order to log into my servers. My SSH key however requires a password. The ...
0
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0answers
8 views

su rails session mysteriously closes by itself

I need help troubleshooting a strange problem. When I ssh into a server I have and do an su rails from root user the session closes by itself: root@ubuntu-server:/4# su rails rails@ubuntu-server:/4$ ...
6
votes
1answer
73 views

Ensure that no console sessions are left logged in (Linux)

On a Linux system with bash as a default shell, I want to configure automatic logout with the following criteria: Console sessions (VGA, serial, remote KVM, etc.) are logged out after a specified ...
7
votes
5answers
4k views

Bash snippet for killing a process until it's dead?

I'm trying to write a robust bash script, and in it I create a background process. At the end of the script, I want to kill it. I have it's PID. I was thinking of somthing like this while [[ ps ef ...
431
votes
34answers
206k views

How can I sort du -h output by size

I need to get a list of human readable du output. However, du does not have a "sort by size" option, and piping to sort doesn't work with the human readable flag. For example, running: du | sort ...
1
vote
1answer
55 views

ansible custom facts returning string not array

I have a custom fact for my servers to retrieve customer data. This works fine on the machine and returning valid json. I can write the output to another facts-file and this works perfectly fine too. ...
29
votes
5answers
2k views

Avoid to keep command in history

I use bash and I would like to avoid some commands being kept in the history. Is it possible to do that for the next command only? Is it possible to do that for the entire session?
1
vote
0answers
36 views

Linux ramdisk transfer files on reboot [closed]

I've created a tmpfs ramdisk, which is mounted at boot through /etc/fstab. The ramdisk should be used to serve content to an apache web server running on the machine. Is there a simple way to ...
7
votes
4answers
4k views

Count number of bytes piped from one process to another

I'm running a shell script that pipes data from one process to another process_a | process_b Does anyone know a way to find out how many bytes were passed between the two programs? The only ...
1
vote
3answers
508 views

SH conditional redirection [closed]

I want to be able to redirect some output of my script to /dev/null based on a command line switch. I don't know how should I do it. In a silly way, it would be something like this (in a too ...
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votes
2answers
28 views

Job control: How to kill a sudo job using the job id

If I run jobs with sudo I can't kill %1 them (Operation not permitted). My first thought was to use sudo kill %1 instead, but that of course doesn't work either because it won't use the bash builtin ...
29
votes
7answers
42k views

How do I run a local bash script on remote machines via ssh?

I am looking for a way to push configuration from one central machine to several remote machines without the need to install anything on the remote machines. The aim is to do something like you ...
109
votes
10answers
154k views

How do I get current Unix time in milliseconds using bash?

How do I get the current Unix time in milliseconds (i.e number of milliseconds since Unix epoch January 1 1970)?
0
votes
1answer
57 views

Installing a software in multiple linux machines using shell scripting in one machine

I will login to one Linux instance using ssh - putty and my goal is to install a software (for ex: I need to download oracle and install it) on 5 Linux machines with one shell script when I run that ...
6
votes
5answers
3k views

Combine multiple unix commands into one output

I need to search our mail logs for a specific e-mail address. We keep a current file named maillog as well as a week's worth of .bz2 files in the same folder. Currently, I'm running the following ...