Linux commands code
ls, cd, cp, mv, grep, chmod. 8 tools.
cat commandWhat cat is really for, why piping it into grep is a habit worth breaking, and the flags that make it genuinely useful.cd commandHow cd works, the shortcuts worth memorising, why it is a shell builtin rather than a program, and how to jump back to where you were.chmod commandPermissions explained properly: what the three digits mean, symbolic versus numeric mode, and why 777 is almost never the right answer.cp commandCopying with cp: recursive copies, preserving attributes, avoiding accidental overwrites, and the trailing-slash trap that catches everyone once.grep commandSearching files with grep: the flags worth knowing by heart, recursive searching, and how to stop it choking on binary files and huge trees.ls commandThe ls command with the flags that matter, sorting and colour options, and the combinations experienced users actually type every day.mv commandMoving and renaming with mv, why it is instant within a filesystem but slow across one, and how to avoid silently clobbering a file.pwd commandWhat pwd reports, the difference between the logical and physical path when symlinks are involved, and how to use it inside scripts.