using sed to replace strings in text files without a text editor

sed 's/sedtest/seedtest/' sedtest.txt > seedtest.txt && mv seedtest.txt sedtest.txt

• s = substitute
• find = sedtest
• replace with = seedtest
• sed won't alter the source file, but a destination file can be specified
• if one wants to effectively update the SOURCE file, simply append the command with 'mv'

see also: https://www.computerhope.com/unix/used.htm

Simple seed script for creating a menu system on linux( from stackoverflow )

#!/bin/bash
# Menu Runner

PS3='Please enter choice: '
opts=("ls" "pwd" "opt3" "Quit")
select opt in "${opts[@]}"
do
    case $opt in
        "ls")
            echo "u chose ls"
            ;;
        "pwd")
            echo "u chose pwd"
            ;;
        "opt3")
            echo "u typed '$REPLY' which calls '$opt'"
            ;;
        "Quit")
            break
            ;;
            *) echo "invalid option $REPLY";;
    esac
done