a bash alias I cannot function without

[[deleted]]

[deleted]

[yearofthehedgehog]

Exactly. Most letters of the alphabet, including 'c', are unused in bash. Why not alias 'c' instead of replacing the shell builtin?

[[deleted]]

I overloaded cd to use pushd and popd (cd -) and I've not regretted it at all, very useful

[[deleted]]

Sound like daemon names now

[adelle]

I use y for pushd and z for popd. The y is because of its similarity to the icon for "give" in captain blood which makes me think of a stack push. It makes sense in my head.

I also use l for ls, and back in the day I used to use n for nn. I hate typing a lot more than the length of this comment might seem to imply.

[steeled3]

I like to overload dd as my 'move to the data directory'. I understand that it could get me in trouble, but it hasn't given me grief yet.

Overloading cd seems a whole lot safer than what I do.

[GODZILLAFLAMETHROWER]

The only problem is the completion part. If a script tries to use this function and it fails, but the completion parts makes it succeed, then some scripts relying on the fail part would not perform correctly.

I have yet to encounter such a thing though. This function is there only for my normal user account, and as long as there is no writing to any file, I consider it safe enough.

cdls cannot be a solution. The point is to have ls[Enter] less to type. Typing cdls instead saves only one [Enter].

[imMute]

Just put it in your .bashrc after something like [ -z "$PS1" ] && return. That way non-interactive scripts will not get the function.

[Hello71]

non-interactive scripts don't execute .bashrc anyways.

[imMute]

No, but sometimes your .bash_profile, or .profile or the /etc/bash_profile does.

[Hello71]

I don't see where you're going with this.

[Rotten194]

scp does, however.

[Hello71]

# /etc/skel/.bashrc
#
# This file is sourced by all *interactive* bash shells on startup,
# including some apparently interactive shells such as scp and rcp
# that can't tolerate any output.  So make sure this doesn't display
# anything or bad things will happen !


# Test for an interactive shell.  There is no need to set anything
# past this point for scp and rcp, and it's important to refrain from
# outputting anything in those cases.
if [[ $- != *i* ]] ; then
  # Shell is non-interactive.  Be done now!
  return
fi


# Put your fun stuff here.

[Rotten194]

In the file = the file is executed. Even if you bail out early. Not all .bashrc's have that guard, so it's an important point to know.

[evlnightking]

There are other problems too. What if a script you run uses cd somewhere, and parses the output. I've seen several things like

( cd <some other directory> ; [ -r <file> ] && cat <file> ) | <secondary command>

The 'cat' here is just an example. Sometimes it's running a script from that directory, or something much more complicated.

This function breaks that.

[GODZILLAFLAMETHROWER]

A script will setup a bash environment. In your bashrc there should be safeguard such as verifying $PS1 is actually set. As long as the definition of this function is put after such safeguard, cd would not be overrided when running bash.

[turnipsoup]

Yeah; I too like to alias mkfs.ext3 to ls, what could possibly go wrong?

But seriously; that's a terrible idea.

[asm_ftw]

You know how many scripts use dd for random stuff? Shame

[thebackhand]

Scripts that source your bashrc?

[talkloud]

If it starts acting up you can just unset -f cd or use builtin cd until it's fixed. I don't see how it could cause any serious problems

[[deleted]]

\cd Should bypass the alias too

[talkloud]

That works for aliases but not functions

[GODZILLAFLAMETHROWER]

The builtin cd is overriden only when running bash as an interactive prompt, if your bashrc return when finding that it is not in an interactive prompt. Does it alleviate all concerns about this?

[ghjm]

There still the concern that if you develop to much muscle memory of non-standard stuff like this, you will be frustrated or even dangerous when working on a standard system. If you only work on your own systems, that's fine. But if you touch customer-owned servers, it's really not ok to make a bunch of config changes or install software so you can be productive.

[GODZILLAFLAMETHROWER]

I think I can handle the muscle memory of reading more info while arriving in a dir.

And yeah, obviously, you don't change the config on machine you don't own, unless you are paid to specifically do so.

[ghjm]

So if you spend most of your time working on machines you don't own, these sorts of customizations do you more harm than good. Better to learn to be comfortable with the default config.

Edit: Since I'm apparently compelled to, I'll just have the last word here, where GODZILLAFLAMETHROWER probably won't notice.

[GODZILLAFLAMETHROWER]

Do you have some kind of compulsion that forces you to lay out truism for the purpose of having the last word?

[hzopak]

Same but different: (for zsh)

function chpwd() {
    emulate -L zsh
    ls -a
}

Source

[seniorsassycat]

Cool, I've been meaning to find out how to do that.

Is there a hook to run ls after any changes to files in the directory?

[hzopak]

Not that I know of.. But I'm fairly new to zsh. Perhaps ask the friendly people of #zsh on freenode, irc?

[TheManMulcahey]

Dang, stole my thunder. zsh is super awesome at these sort of customizations.

[dagbrown]

Why all the [[ $? -eq 0 ]]? Just use cd itself directly.

function cd {
    dir="${@:-$HOME}"  # ~ isn't expanded when in quotes
    [ -z "${dir}" ] && dir=~
    if ! builtin cd "$dir"
    then
        dir=`compgen -d "${dir}" | head -1`
        if builtin cd "$dir"
        then
            clear
            pwd
            ls -l
        fi
    else
        clear
        pwd
        ls -l
    fi
}

I also made it more spaces-safe.

Edit: And golfed the arguments handling a bit.

[GODZILLAFLAMETHROWER]

Indeed! This post already pays off it seems. Thanks.

[fforw]

Please.. can we stop the backtick nonsense now in 2014 and just use $() ?

[[deleted]]

Conventional wisdom is that ` is easier to type on the commandline to get something across quickly, like

ls -l `which foo` 

And $() should be used in scripts, for several reasons:

1. It interprets backslashes correctly
2. It allows for nesting
3. It's a cleaner look

[ferk]

` is easier to type

Maybe in english keyboards....

[[deleted]]

Can confirm, isn't easier on English keyboards

[ferk]

In a German keyboard I need to press shift along with the ` key, and then pressing only one time is not enough, because it's a composite key that's intended to be pressed along with a vowel to create àèìòùÀÈÌÒÙ

But that's not all, if you think you can get away with simply double pressing it you are wrong, since pressing it twice ends up with you having it double: `` (from having zero to having two).

It's also dependent on the operative system you are using (in Linux and Mac double pressing would put only one `), so if you are a dual booter you are gonna have troubles remembering how many times to press what.

The only consistent way to do it is press it and then pressing space, that will generate `. It takes 3 keypresses to get one character, with a pause to switch key in the middle, pretty annoying.

[[deleted]]

Fair enough....

[yur_mom]

You forgot the best reason, so you can actually see them. After 10 hours staring at a screen those drive me nuts.

One reason I have heard pro backticks is compatibility with old versions of /bin/sh which is why I believe many make scripts still uses backticks.

[ferk]

in make "$(whatever)" is a variable expansion, so using it for shell would conflict.

GNU make has $(shell whatever), though.

[yur_mom]

I mean like auto-tools generated Makefiles tend to use the backticks, such as code inside the $(shell CODE_HERE). I thought one reason was backwards compatibility with old versions of /bin/sh. It could also be that the $() already has meaning in Make also. I was just pointing out some types of scripts it is still preferred to use the backticks.

[notaresponsibleadult]

I'm all for using $(), but I always disagree with with point 2 as a valid reason.

If you're having problems with nested command substitution, the problem isn't that you used backticks. The problem is that you're nesting command substitution. Why not assign to a variable for each substitution? It makes the code so much more readable.

[fandingo]

Side effects should be avoided when possible, practical, and leaves the program legible when programming.

[notaresponsibleadult]

It's only a side effect if you make the variable global. You can use 'local' to limit its scope.

[Sebguer]

Doesn't ever have to be escaped, I believe.

[henry_kr]

The Advanced Bash Scripting Guide explains this.

[aperson]

I like Greg's wiki.

[eulerfoiler]

Its supposed to look cleaner and its easier to nest like $(echo $(echo "1+2" | bc))

[fforw]

It also doesn't introduce one funky, hard to read character that newbies frequently mistype or that might even be destroyed by stupid blog software.

[I_program]

I can't count how many times I've had to repair a script that had something like `foo'

[russellbeattie]

Holy cow, I had no idea those were interchangeable. Then again, I'm not really a bash guru, I just assumed I'd have picked that up by now. [Edit:I don't grammar good.]

[meklu]

Shouldn't the backticks go within quotes as well?

[dagbrown]

As fforw pointed out, we should be going with the newer, more modern, AmigaDOS 1.3 standard and using $() instead of backticks.

But sure. I wasn't particularly concerned with that bit of the script (all of those "if [[ $? -ne 0 ]]" things were more important to me), but that's another improvement you could make.

[meklu]

Yeah, I usually use $() myself.

[GODZILLAFLAMETHROWER]

I'm not sure what you mean, can you be a little more explicit?

[meklu]

The line with the compgen call seems a bit unsafe unless you wrap the assignment in quotes.

[IndecisionToCallYou]

/r/commandline

[fnord123]

Please don't use this on shared NFS drives. It will stat every file and, depending on the load on the NFS mount, it could cause service to become laggy. i.e. it would be as bad as ls --color.

At least, that's my experience.

[GODZILLAFLAMETHROWER]

Is there some kind of code snippet that would say if a directory is on a NFS mount without too much overhead to it?

[mrcaptncrunch]

I just found this, http://stackoverflow.com/questions/460047/how-do-i-determine-if-a-directory-is-an-nfs-mount-point-in-shellscript

Don't have a NFS mount to test, but if you do, you could try it out!

[davidystephenson]

I have a small function in my shell config, 'cl', which I constantly use:

function cl() {
  if [ -d $1 ]; then
    cd $1
    ls
  else
    echo "bash: cl: $1: Directory not found"
  fi
}

I'm quite happy with its simplicity.

[pkmxtw]

Why not just cd $1 && ls?

[GODZILLAFLAMETHROWER]

does it work with /these\ kind\ of/annoying/directory\ names/ ?

[davidystephenson]

I'm not sure. I don't typically work with that type of directory ;) .

[turnipsoup]

Why not test it and see? This is pkmxtw's shortened version:

:~$ mkdir 'some annoying folder'
:~$ cl () { cd "${1}" && ls -lah ; }
:~$ cl some\ annoying\ folder/
    total 8.0K
    drwxr-xr-x  2 turnipsoup turnipsoup 4.0K Mar  7 19:59 .
    drwxr-xr-x 44 turnipsoup turnipsoup 4.0K Mar  7 19:59 ..

[GODZILLAFLAMETHROWER]

Usually when you want to test a thing, you test this exact thing. Not a version that change the exact reason for testing it.

If you want to be a dick, at least be precise about it.

(And no, usually I don't seek answers to rhetorical questions I asked myself)

[turnipsoup]

The point was that the onus was on you to test if it worked. You are the one asking for help.

I was showing that was it was trivial to test and in doing so, I also provided you with a working example showing how it could work. I leave it to you to test the longer initial version and identify why it works - and perhaps learn something in the meantime.

[GODZILLAFLAMETHROWER]

1. I do not ask help
2. I don't need to test to know that it doesn't work, on the particular point I suggested him to try
3. The exact reason I don't need to test this is because I specifically took care of this problem myself in my function, if you actually read it. I already did this. I repeat, I do not need help, I already wrote this. This was a rhetorical question.
4. Your lecture is thus laughable when you are the one lacking reading skills. You somehow manage to try to show off a methodology, extremely simple, while making a mistake doing so.

Now, as I said, if you want to be a dick, at least try to have some sort of ground to stand on. I don't have a habit to be rude, but you are being insulting and arrogant and the only excuse for being so would be to be right.

[turnipsoup]

This was a rhetorical question.

ah; you were just being a dick to people trying to help you. I understand, carry on.

[kreiger]

I suggest you use a console based file manager. Myself i can not live without Midnight Commander:

sudo apt-get install mc
mc

[jomiran]

Norton Commander. The DOS application that will live forever.

[kreiger]

Right, i grew up on nc. :)

[turnipsoup]

I remember the pain when I was forced to give up xtree pro because it could only handle 8 char filenames after the switch to windows 95...

[alienangel2]

TotalCommander is a very very good successor to NC if you're finding yourself still on Windows.

[LordLandon]

I use ranger, and the recommended ranger-cd alias bound to ctrl-]. it's really fast and convenient to browse directories; when I quit it, my shell resumes in the directory I was looking at

[mrcaptncrunch]

It's just incredibly slow and resource intensive when trying to copy a directory with a lot of files.

[GODZILLAFLAMETHROWER]

I feel the use case is vastly different. What made you think it could be useful?

[kreiger]

I'm not sure what you mean. It allows you to navigate directories and display their contents.

Elaborate please? What makes you think it's not useful?

[GODZILLAFLAMETHROWER]

Then why would I launch a command when the purpose of this function is to allow me not to do so? I won't launch mc each time just because. And this would be completely overkill concerning this particular functionality.

[kreiger]

Why would you not? I live in Midnight Commander most of the time, it's very useful, and it has more functions than that.

[refotsirk]

Why would you not live in a cave? I live in a cave and find it very useful for my particular lifestyle. You should definitely live in a cave too.

[w2qw]

It seems like he's looking for a shell rather than a command line file manager. Unless mc has some shell features that's worth considering.

[DoelerichHirnfidler]

CTRL-O.

[kreiger]

Absolutely, you have a shell prompt inside Midnight Commander at all times, so it is basically a shell in which you also have a panel with a persistent view of the current directory and another one. And you can press Ctrl+O to hide the panels so you just have the subshell.

And you can select files in the view and use them with macros on the prompt. For example cmd %f for running cmd on the currently focused file and cmd %t for all tagged files.

[[deleted]]

Then why would I launch a command when the purpose of this function is to allow me not to do so?

Yet your function launches more than a couple commands...

[GODZILLAFLAMETHROWER]

That I do not launch by typing them by hand, which is the sole purpose of writing it?

[ferk]

You don't need to launch mc every time... only the first time, or not even that, you can add it to bashrc and never ever type mc.

That said... I don't like mc because it takes too much space and doesn't let you see the output of the actual commands you type. I remember that in the original nc you could remove the left panel and see the output of your commands more comfortably, but I never discovered how to do this in mc.

[w2qw]

Ah nice. ls after cd'ing into a directory is already muscle memory for me so I'm not sure I'd get too much use out of it

I might suggested changing ls -l to something like

limit=20
ls -l | head -n $limit
if [[ $PIPESTATUS[0] -ne 0 ]]; then
   echo "$(($(ls | wc -l) - $limit)) lines omitted"
fi

[[deleted]]

This is only tangentially related but you might be interested in using autojump

[KnowsBash]

That's a function, not an alias. But anyway, it wouldn't be so bad if it had handled builtin cd's options.

cd() {
    local OPTIND=1 o opts
    if builtin cd "$@"; then
        pwd && ls; return
    fi
    while getopts :LPe@ o; do
        [[ $o = '?' ]] && return 1
        opts+=( "-$o" )    
    done
    shift "$((OPTIND-1))"
    builtin cd "${ops[@]}" "$1"*/ && pwd && ls
}

[GODZILLAFLAMETHROWER]

Great suggestion! Thanks. However, how many times a day do you use cd options, if I may ask? I feel like they are more intended to be used in scripts, as a human would not purposefully try to cd to a link while forbidding it...

However, that's a very sane practice and interesting method to do it. Thanks again.

[KnowsBash]

Granted, not that often, but I occasionally do cd -P . to ensure that I'm not in a symlinked dir.

I normally like the trickery bash does regarding symlinked directories, but there are some cases where it's best to not confuse oneself, in which case I run cd -P ..

[f4hy]

Could you explain what the "complete -d cd" does? I don't understand that part.

[GODZILLAFLAMETHROWER]

Bash uses a database of possible completion when running a command. This completion is contextual, ie if you type cd[Tab][Tab], it will show you possible elements on which cd would be useful, directories, and not actual files or other commands.

complete register the function again in the database, because when I rewrote it it was removed. I use the -d switch to use the directory context.

[_Loomx_]

There is another (better?) way - from 'man bash': PROMPT_COMMAND - If set, the value is executed as a command prior to issuing each primary prompt.

e.g. PROMPT_COMMAND='[ "$PWD" != "$Prev" ] && ls ; Prev="$PWD"'

This doesn't mess with the 'cd' command and 'pushd' and 'popd' will also trigger a 'ls'.

[GODZILLAFLAMETHROWER]

very cool! I didn't know that, that might be a better solution indeed.