How to run command from file using Bash?

Question

I want to write Bash script witch will allow me to run commands from a text file.

In file will be special word: "secretcommand" and the proper command in next line.

Example of text file:

This is

my

secretcommand

pwd

bash

script

Now I want in my script to find a "secretcommand". I wanted to use grep -n so I could get the line of this word and then somehow add + 1 to that line so I get number of next line where is proper command. And finally I want to run this command. I wanted use sed -f but it wasn't workin or I'm doing something wrong.

Can you help me please?

try to see this topic http://stackoverflow.com/questions/27968451/display-exact-output-of-unix-command-from-bash-script if that concide with what you try to do — aston
– aston, Commented Jan 28, 2017 at 1:25

Fred · Accepted Answer · 2017-01-28 10:57:29Z

1

This script will take one argument, the path for your text file:

#!/bin/bash
while read -r line
do
  [[ "$line" =~ ^secretcommand$ ]] || continue
  read -r cmd || break
  eval "$cmd"
  break
done<"$1"

It requires the whole line to match exactly secretcommand, with no extra spacing (this can be modified by altering the regular expression matching between double brackets [[ ]].

Please note that using "eval" on arbitrary data is generally not a good idea from a security perspective, but given your purpose is precisely to execute code from data files, I assume you understand the risks.

edited Jan 28, 2017 at 10:57

answered Jan 28, 2017 at 1:37

Fred

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Gab · Accepted Answer · 2017-01-28 01:42:48Z

0

You can try to use awk to echo the proper command and then execute it, something like this:

awk '/secretword/ { flag = "1" } { if(flag == "1" && $1 != "secretword") { print $1; exit 0 } }' <file | bash -

edited Jan 28, 2017 at 1:42

answered Jan 28, 2017 at 1:30

Gab

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Shiping · Accepted Answer · 2017-01-28 01:57:57Z

0

This script take the file with secret command as the commandline argument.

#!/bin/bash

words=`cat $1`
found=0
command=''
for word in ${words[@]};
do
   if [ $word = 'secretcommand' ]; then
      found=1
   elif [ $found -eq 1 ]; then
      found=0
      command=$word
   fi
done
if [ $command != '' ]; then
   $command  # run the found command
fi

answered Jan 28, 2017 at 1:57

Shiping

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