I wouldn’t want most things to work this way:

    $ rm file.bin
    $ rm —-commit file.bin
    $ cat foo.txt > bar.txt
    $ cat foo.txt | tee —-write-for-real bar.txt
    $ cp balm.mp3 pow.mp3
    $ cp —-i-mean-it balm.mp3 pow.mp3

There is a time and a place for it but it should not be the majority of use cases.

▲ Darfk 13 hours ago | parent | next [-]

Totally agree it shouldn't be for basic tools; but if I'm ever developing a script that performs any kind of logic before reaching out to a DB or vendor API and modifies 100k user records, creating a flag to just verify the sanity of the logic is a necessity.

▲ Joker_vD 13 hours ago | parent | next [-]

    if [ -n "$DRY_RUN" ] ; then
        alias rm='echo rm'
        alias cp='echo cp'
    fi

Of course, output redirects will still overwrite the files, since the shell does it and IIRC this behaviour can't be changed.

▲

digiown 12 hours ago | parent [-]

set -o noclobber

	▲	8 hours ago \| parent [-]
		[deleted]

▲ james_marks 13 hours ago | parent | prev [-]

Yep. First thing I do for this kind thing is make a preview=true flag so I don’t accidentally run destructive actions.

▲ digiown 12 hours ago | parent | prev | next [-]

For most of these local data manipulation type of commands, I'd rather just have them behave dangerously, and rely on filesystems snapshots to rollback when needed. With modern filesystems like zfs or btrfs, you can take a full snapshot every minute and keep it for a while to negate the damage done by almost all of these scripts. They double as a backup solution too.

▲ ronjakoi 10 hours ago | parent | prev | next [-]

I used to have alias rm='rm -i' for a few years to be careful, but I took it out once I realised that I had just begun adding -f all the time

	▲	Mawr 12 minutes ago \| parent \| next [-]
		Yeah, but that's because it's implemented poorly. It literally asks you to confirm deletion of each file individually, even for thousands of files. What it should do is generate a user-friendly overview of what's to be deleted, by grouping files together by some criteria, e.g. by directory, so you'd only need to confirm a few times regardless of how many files you want to delete.
	▲	wonger_ 4 hours ago \| parent \| prev [-]
		See also rm -I (capital i), which only prompts when deleting directories or >3 files

▲ hdjrudni 13 hours ago | parent | prev | next [-]

Even in those basic examples, it probably would be useful. `cp` to a blank file? No problem. `cp` over an existing file? Yeah, I want to be warned.

`rm` a single file? Fine. `rm /`? Maybe block that one.

	▲	Izkata 8 hours ago \| parent [-]
		That last one would error without doing anything anyway because it's not recursive.

▲ Mawr 14 minutes ago | parent | prev [-]

Uhuh:

    $ rm -rf /

    rm: it is dangerous to operate recursively on '/'
    rm: use --no-preserve-root to override this failsafe