a - patch command patch command is used to apply a diff file to an original source It is useful for applying bug fixes, and updating software source syntax → patch [options] original-file patch-file common options: -b → makes a backup file -c → interpret the patch file as a ordinary context diff -f → force We create one file and another one that is different diff -u config_v1.ini config_v2.ini config_patch.diff → creates a patch file patch config_v1.ini config_patch.diff → apply the patch to the file
b - tr command tr command is used to delete or translate characters It reads from standard input and writes to standard output It performs characters replacements according to a mapping defined by the first argument syntax → tr [options] SET1 echo "hello" | tr 'e' 'E' → changes e to E echo "hello world" | tr 'lo' 'LO' → changes lo to LO echo "hello world" | tr -d 'lo' → deletes lo echo "HELLO WORLD" | tr 'A-Z' 'a-z' → changes all capital letters to small