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Accepted
Jenny
Asked: 2019-04-02 14:21:37 +0800 CST

Write a regular expression which catches user $HOME in shellscripting

  • 772

I'd like to write a regex in shellscript which would compare the user input path to user$HOME. Then it would raise an error in case the user input path contains the user $HOME. The home folder normally starts with /ort/home but /ort part is not a must. When I run it always gives a valid path although I clearly enter an invalid path. What am I doing wrong? Thanks. Please refer following link[1] if necessary to see how regex are used in shellscript

My attempt is as follows

#!/bin/bash

function user_input () {

        read -p "Type the path for project1:" user_path

        string1="${HOME}"
        echo "$string1"

        if [ "$user_path" = "$string1 | /ort/home/+.* |  .*+/home/+.*"  ]; then 
             echo "Not a valid path, contains $HOME directory"        
        else
             echo "valid path"
        fi
}

function main() {

user_input
}

main

Terminal output

Please note first entry is a valid path and other two are invalid paths.

jenny@server32:~$ ./test.sh 
Type the path for project1:/scratch/random
/ort/home/j/jen
valid path

jenny@server32:~$ ./test.sh 
Type the path for project1:/ort/home/j/jen
/ort/home/j/jen
valid path

jenny@server32:~$ ./test.sh 
Type the path for project1:/ort/home
/ort/home/j/jen
valid path

[1]https://stackoverflow.com/questions/2237080/how-to-compare-strings-in-bash

scripts command-line bash regex

1 Answers

  1. Best Answer

    The case command uses glob wildcards which are pretty easy to work with:

    case "$user_path" in
    "$HOME"*) echo "Error: path cannot be in your HOME" ;;
    */home/*) echo "Error: cannot have 'home' in the path" ;;
    *) echo "Thank you, valid path" ;;
esac
    • 2