Alias with variable in bash

Question

I want to create an alias in bash like this:

alias tail_ls="ls -l $1 | tail"

Thus, if somebody types:

tail_ls /etc/

it will only show the last 10 files in the directory.

But $1 does not seem to work for me. Is there any way I can introduce variables in bash.

csh and tcsh support parameters like `$1` in alias; bash doesn't. — Keith Thompson, Dec 31 '14 at 02:13

score 222 · Accepted Answer · edited Mar 16 '13 at 06:07

222

I'd create a function for that, rather than alias, and then exported it, like this:

function tail_ls { ls -l "$1" | tail; }

export -f tail_ls

Note -f switch to export: it tells it that you are exporting a function. Put this in your .bashrc and you are good to go.

edited Mar 16 '13 at 06:07

Aditya Sanghi

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answered Dec 14 '10 at 10:36

Maxim Sloyko

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It's usually not necessary to export a function. – Dennis Williamson Dec 14 '10 at 10:58
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@Dennis, yeah, you are right, for a simple alias that won't be necessary, but it is there just in case you want to use it in some derived shell/process. – Maxim Sloyko Dec 14 '10 at 11:10
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Why do I need an alias if I can call the function directly? – mrudult Apr 26 '16 at 17:17
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This is not an alias-base solution, its a function-base solution .. It's working smoothly – Maher Abuthraa Aug 04 '17 at 09:31
Technically almost everything is a file to Linux, so functions are files, alias & tail are files, even processes are files. – NotoriousPyro Sep 03 '18 at 21:04

score 43 · Answer 2 · answered Feb 21 '16 at 21:47

43

alias tail_ls='_tail_ls() { ls -l "$1" | tail ;}; _tail_ls'

answered Feb 21 '16 at 21:47

Javier López

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That's a creative approach. Definitely solves the issue if they **need** to use an alias rather than a function… I think I'd prefer a function if those are an option instead, but a very neat solution to keep in mind for when the right situation arises! – lagweezle Jul 21 '16 at 16:00

score 38 · Answer 3 · edited Aug 21 '14 at 13:39

38

The solution of @maxim-sloyko did not work, but if the following:

In ~/.bashrc add:

sendpic () { scp "$@" mina@foo.bar.ca:/www/misc/Pictures/; }

Save the file and reload
```
$ source ~/.bashrc
```
And execute:
```
$ sendpic filename.jpg
```

original source: http://www.linuxhowtos.org/Tips%20and%20Tricks/command_aliases.htm

edited Aug 21 '14 at 13:39

fedorqui

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answered Jan 09 '13 at 12:20

jruzafa

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@jruzafa, In which context, you assert that 'The solution of maxim-sloyko works did not work' whilst his/her solution worked for myself. – Herpes Free Engineer Oct 23 '17 at 10:08
You can add your functions to bashrc with: `typeset -f >> ~/.bashrc` – Noam Manos Nov 27 '18 at 13:28

score 4 · Answer 4 · answered Jun 16 '16 at 08:58

4

You can define $1 with set, then use your alias as intended:

$ alias tail_ls='ls -l "$1" | tail'
$ set mydir
$ tail_ls

answered Jun 16 '16 at 08:58

J. Chomel

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What is set doing here? How does this work? – Brijesh Mar 29 '21 at 03:07
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@Brijesh, `set mydir` defines `$1` as `mydir` that would be the intended directory... not that great. – J. Chomel Mar 29 '21 at 08:17

l0b0 · Answer 5 · 2016-02-21T22:50:22.987

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tail_ls() { ls -l "$1" | tail; }

edited Feb 21 '16 at 22:50

answered Dec 14 '10 at 10:31

l0b0

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Please fix the syntax error (missing `;` before `}`) and double-quote `$1` so as to also support filenames with embedded whitespace and other shell metacharacters. – mklement0 Feb 21 '16 at 22:22

score 0 · Answer 6 · answered Oct 04 '13 at 13:11

If you are using the Fish shell (from http://fishshell.com ) instead of bash, they write functions a little differently.

You'll want to add something like this to your ~/.config/fish/config.fish which is the equivalent of your ~/.bashrc

function tail_ls
  ls -l $1 | tail
end

Alias with variable in bash

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