Bash: sed for String Substitution

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