skuja - Developer IT

Bash - how can i pass variable to command and read its output

- by Skuja

In my bash script i want to execute command that will find lines in a file that starts with a keyword which is stored in a variable like this: keyword="key" result=(`cat path/to/my/file | grep '^$keyword'`)

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WEB based HPC cluster node management

- by Skuja

Hello, i am working on my school diploma thesis. The main goal is to create web based application where logged users could see free and busy nodes, turn them on and off, see what process they are running etc. Figured out that i could do something like this - write some cron daemon that would run every 30seconds or so, and it could run ping utility…

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Escape characters contained by bash variable in regex pattern

- by Skuja

In my bash script, i am trying to execute following Linux command: sed -i "/$data_line/ d" $data_dir $data_line is entered by user and it may conatain special characters that could brake regex. How can i escape all of the possible special characters in $data_line before i execute sed command?

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Check which nodes of Beowulf HPC cluster system are free from PHP app?

- by Skuja

I am working on my diploma thesis project. I have access to 32Node Dell poweredge HPC cluster system with Linux(Debian i think) installed on it. My first goal is to create web (PHP) app where logged users could see free and busy nodes, turn them on and off. I am planning to do something like this - write some cron daemon that would run every…

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C - How can i get return value of command passed to execl?

- by Skuja

I know that it is possible to read commands output with a pipe? But what about getting return value ? For example i want to execute: execl("/bin/ping", "/bin/ping" , "-c", "1", "-t", "1", ip_addr, NULL); How can i get returned value of ping command to find out if it returned 0 or 1?

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MySQL count problem

- by Skuja

I have 3 tables users(id,name),groups(id,name) and users_groups(user_id,group_id). users and groups have many to many relationship, so the third one is for storing users and groups relations. I would like to select all the data from groups with user count in each group. So far I came up with this: SELECT groups.*,…

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c, pass awk syntax as argument to execl

- by Skuja

I want to run following command in c to read systems cpu and memory usage: ps aux|awk 'NR > 0 { cpu +=$3; ram+=$4 }; END {print cpu,ram}' I am trying to pass it to execl command and after that read its output: execl("/bin/ps", "/bin/ps", "aux|awk", "'NR > 0 { cpu +=$3; ram+=$4 }; END {print…

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