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30 votes
Accepted

Run a script from anywhere

You want to type abspath, but the program is named abspath.sh. The problem is not regarding whether it is in the PATH, but the fact that you are simply not using its name to call it. You have two ...
Michael Hampton's user avatar
24 votes
Accepted

How to compress this mysqldump?

I think you can just do this. /usr/bin/mysqldump -h $mysql_host -u $mysql_username -p$mysql_password $mysql_database | gzip -9 -c > $backup_path/$today/$mysql_database-`date +%H%M`.sql.gz
Alex Gitelzon's user avatar
22 votes

How do you set a locale non-interactively on Debian/Ubuntu?

Based on the fine work in @EirikW's answer. Specific to a Dockerfile: ENV LANG=en_GB.UTF-8 RUN apt-get install -y locales && \ sed -i -e "s/# $LANG.*/$LANG UTF-8/" /etc/locale....
mafrosis's user avatar
  • 401
11 votes

Echo each shell script command with a timestamp

In Bash, you can use PS4 - which is used by set -x to prefix tracing output. PS4='+ $(date "+%s.%N")\011 ' set -x ... \011 is the horizontal tab character
ArtBIT's user avatar
  • 211
11 votes

Get list of transferred files from rsync?

Use the --out-format option According to the man page: Specifying the --out-format option will mention each file, dir, etc. that gets updated in a significant way (a transferred file, a ...
flu's user avatar
  • 211
11 votes
Accepted

Automated graceful reload of gunicorn in production

Add the following to the systemd service file for gunicorn, or add it as an override: ExecReload=/bin/kill -HUP $MAINPID You can then reload with systemctl reload gunicorn.
jordanm's user avatar
  • 899
11 votes

Robust way to resolve a DNS address in a script (IPv4 (A) and IPv6 (AAAA))?

I'm unsure if you want to actually query nameservers or rather rely on your system's name resolution: $ getent ahosts one.one.one.one. | awk '{ print $1 }' | sort -u 1.0.0.1 1.1.1.1 2606:4700:4700::...
fuero's user avatar
  • 9,759
10 votes

What does a minus sign inside of dollar brackets of a shell script mean?

It should be emphasized that this means an unset variable. Not an empty one. And to put to comparison with :-, which will use default value (the one after minus sign) if variable is unset or null (as ...
papo's user avatar
  • 209
10 votes
Accepted

FreeBSD rc.d script doesn't start as a daemon

The RC script itself is not intended to daemonize, but is expected to start and stop the daemon. If your service does not have an option to start as a daemon, you can use daemon(8) to manage that ...
Richard Smith's user avatar
9 votes
Accepted

shell script to delete 6 month old logs from log file

The solution really is to use logrotate: it works very well, and it can also compress the rotated log. If you really don't want to use logrotate, you had to manually cat/copy the relevant section of ...
shodanshok's user avatar
  • 50.9k
8 votes
Accepted

Echo each shell script command with a timestamp

in Bash, execution of code after each command can be achieved using the "trap" builtin and the "DEBUG" level. in bash do: help trap or refer to bash manual page, and look for the trap section ...
laurent's user avatar
  • 126
8 votes

How do you set a locale non-interactively on Debian/Ubuntu?

For me it was necessary to set the additional 3 ENV-Vars: # - Set the locale + timezone -------------------------------------------------- RUN echo "Europe/Vienna" > /etc/timezone && \ ...
Mike Mitterer's user avatar
8 votes

Loop through servers and run command

There is solution with -n -x parameters: http_status=$(ssh -nx name ps -ef | grep -v grep | grep $service | wc -l) The -x disables X11 forwarding to get rid of possible X11 forwarding request failed ...
Jaroslav Kucera's user avatar
8 votes
Accepted

Closing All Shared Files on the Network

The command you are using is not a native PowerShell command. However, PowerShell does come with a lot of functions to control SMB connections and shares. What you are looking for could be this: Get-...
Tobias's user avatar
  • 1,246
7 votes

Using curl with cookies

It is possible that their website is authenticating the session stored in the cookies by redirecting them first to the login page. Then their login page will redirect back to the appropriate page as ...
Carlo Miguel Cruz's user avatar
7 votes

How to compress this mysqldump?

Just 'pipe the output' to gzip The command would become this: /usr/bin/mysqldump -h $mysql_host -u $mysql_username -p$mysql_password $mysql_database | gzip > $backup_path/$today/$mysql_database-`...
Bert's user avatar
  • 3,043
7 votes
Accepted

Loop through servers and run command

You need to redirect the stdin of SSH command in your loop to nowhere to prevent reading all your lines. This should do it: http_status=$(ssh $name "ps -ef | grep -v grep | grep $service | wc -l" <...
Khaled's user avatar
  • 37k
7 votes
Accepted

Can't access instance after setting up iptables rules

For rules in the OUTPUT chain you should specify the source port match (--sport), not the destination port (--dport). Anyway DROP policy in the OUTPUT chain isn't a common practice. Read the iptables ...
Anton Danilov's user avatar
7 votes

Robust way to resolve a DNS address in a script (IPv4 (A) and IPv6 (AAAA))?

You are on the right track with dig. You can suppress that particular cookie related error (per the man page). Below, I am also choosing to redirect all errors to /dev/null just in case, as you wanted ...
JG7's user avatar
  • 196
7 votes

Robust way to resolve a DNS address in a script (IPv4 (A) and IPv6 (AAAA))?

getent ahosts[v4|v6] and generally anything that uses getaddrinfo() is the right answer, as it will use the same name resolution mechanisms (DNS, mDNS, NetBIOS, NIS, LDAP…) as the rest of the system, ...
u1686_grawity's user avatar
6 votes

Run a script from anywhere

This code is small enough that I would code it as a shell function: abspath() { echo "$(dirname "$(readlink -e "$1")")/$(basename "$1")" } And yes you do want all those quotes.
glenn jackman's user avatar
6 votes

Installing and configuring phpmyadmin completely through a shell script

Basically the first thing to do is skipping any interactive post-install configuration steps. export DEBIAN_FRONTEND=noninteractive apt-get -yq install phpmyadmin This will skip all the questions ...
Esa Jokinen's user avatar
  • 50.1k
6 votes
Accepted

How to start a jar file using systemd

Using systemd directives in place of shell results in a more consistent environment. This includes not relying on $PATH or the working directory by providing full paths where they are known. Neither &...
John Mahowald's user avatar
6 votes

Trying to execute this shell script but getting this error

Your script has DOS line endings. Convert them to Linux line endings either in your editor or with tools like dos2unix, recode etc. DOS/Windows usually ends lines with CR+LF, while Linux only uses ...
Sven's user avatar
  • 99.6k
6 votes
Accepted

Running a binary as a service in RedHat/CentOS

Have you looked into the below error message? Apr 16 06:29:32 matrix-pipeline-b-01 executePipeline.sh[10195]: sudo: no tty present and no askpass program specified Apr 16 06:29:32 matrix-pipeline-b-...
Timothy Pulliam's user avatar
6 votes
Accepted

Using blkid to check if an attached EBS volume is formatted

You can check the details of a specific device and act based on that: blkid --match-token TYPE=ext4 /dev/nvme123 || mkfs.ext4 -m0 /dev/nvme123 What this does is: blkid checks whether /dev/nvme123 ...
MLu's user avatar
  • 25.5k
6 votes
Accepted

Is it possible to listen to a TCP port only with a shell, with no additional tools?

No, a basic Bourne/POSIX shell (/bin/sh) cannot be expected to include any built-in facilities for TCP connections. See comparision of command shells in Wikipedia. The bash shell would have TCP and ...
telcoM's user avatar
  • 4,618
5 votes

How do I sleep for a millisecond in bash or ksh

I had the same problem (no shell usleep on Solaris) so I wrote my own thus: #include "stdio.h" int main(int argc, char **argv) { if(argc == 2) { usleep(atoi(argv[1])); } return 0; } ...
jrichemont's user avatar
5 votes

How to compress this mysqldump?

You can pipe it though gzip (or bzip2, pbzip2, xz, etc...) like so: /usr/bin/mysqldump -h $mysql_host -u $mysql_username -p$mysql_password $mysql_database | gzip -c > $backup_path/$today/$...
Ryan Babchishin's user avatar
5 votes
Accepted

Select remote database from bash

you need a subshell. try this: count=$(mysql -u mysql -pMysql123 -h xxx.xxx.xxx.xxx MYDBNAME -sse "select count(column) from TABLE where column=1234;") if [ $count -gt 0 ] then echo " greater ...
gbolo's user avatar
  • 633

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