How can I pass variables from awk to a shell command?
you are close. you have to concatenate the command line with awk variables: awk ‘{system(“wc “$1)}’ myfile
shell
nginx: use environment variables
With NGINX Docker image Apply envsubst on template of the configuration file at container start. envsubst is included in official NGINX docker images. Environment variable is referenced in a form $VARIABLE or ${VARIABLE}. nginx.conf.template: user nginx; worker_processes 1; error_log /var/log/nginx/error.log warn; pid /var/run/nginx.pid; events { worker_connections 1024; } http { server { listen 80; location … Read more
How to run a script at the start up of Ubuntu? [closed]
First of all, the easiest way to run things at startup is to add them to the file /etc/rc.local. Another simple way is to use @reboot in your crontab. Read the cron manpage for details. However, if you want to do things properly, in addition to adding a script to /etc/init.d you need to tell … Read more
Write byte at address (hexedit/modify binary from the command line)
printf ‘\x31\xc0\xc3′ | dd of=test_blob bs=1 seek=100 count=3 conv=notrunc dd arguments: of | file to patch bs | 1 byte at a time please seek | go to position 100 (decimal) conv=notrunc | don’t truncate the output after the edit (which dd does by default) One Josh looking out for another 😉
Remove part of path on Unix
If you wanted to remove a certain NUMBER of path components, you should use cut with -d”https://stackoverflow.com/”. For example, if path=/home/dude/some/deepish/dir: To remove the first two components: # (Add 2 to the number of components to remove to get the value to pass to -f) echo $path | cut -d”https://stackoverflow.com/” -f4- # output: # some/deepish/dir … Read more
Can I call a function of a shell script from another shell script?
Refactor your second.sh script like this: func1 { fun=”$1″ book=”$2″ printf “func=%s,book=%s\n” “$fun” “$book” } func2 { fun2=”$1″ book2=”$2″ printf “func2=%s,book2=%s\n” “$fun2” “$book2” } And then call these functions from script first.sh like this: source ./second.sh func1 love horror func2 ball mystery OUTPUT: func=love,book=horror func2=ball,book2=mystery
How to grep a text file which contains some binary data?
grep -a It can’t get simpler than that.
How to run a command in the background and get no output?
Use nohup if your background job takes a long time to finish or you just use SecureCRT or something like it login the server. Redirect the stdout and stderr to /dev/null to ignore the output. nohup /path/to/your/script.sh > /dev/null 2>&1 &
Block Comments in a Shell Script
In bash: #!/bin/bash echo before comment : <<‘END’ bla bla blurfl END echo after comment The ‘ and ‘ around the END delimiter are important, otherwise things inside the block like for example $(command) will be parsed and executed. For an explanation, see this and this question.
Curl to return http status code along with the response
I was able to get a solution by looking at the curl doc which specifies to use – for the output to get the output to stdout. curl -o – -I http://localhost To get the response with just the http return code, I could just do curl -o /dev/null -s -w “%{http_code}\n” http://localhost