I have an executable file mpiexec, whose full path is ~/petsc-3.2-p6/petsc-arch/bin/mpiexec. Since I want to execute this command in different directories (without having to retype the entire path), I setup an alias in my home .bashrc file:

alias petsc="~/petsc-3.2-p6/petsc-arch/bin/mpiexec"  

which allows me to execute this mpiexec file at the command prompt easily by typing:

petsc myexecutable

I tried to write a shell script file, named script, using my new alias petsc as a command. After giving my shell script the appropriate permissions (using chmod), I tried to run the script. However, it gave me the following error:

./script: line 1: petsc: command not found

I know that I could just write the full path to the mpiexec file, but it is cumbersome to write the full path everytime that I want to write a new script. Is there a way that I can use my alias petsc inside the script file? Is there a way I can edit my .bashrc or .bash_profile to make this happen?

  • How about adding the alias to .bash_aliases ? Also how about aliasing the absolute path instead of relative path like alias petsc='/home/user/petsc-3.2-p6/petsc-arch/bin/mpiexec' – Nitin Venkatesh Jan 26 '12 at 18:17
  • @nitstorm: Neither solution seems to work... I still get the same error as before – Paul Jan 26 '12 at 18:21
up vote 59 down vote accepted
  1. In your shell script use the full path rather then an alias.

  2. In your shell script, set a variable, different syntax

    petsc='/home/your_user/petsc-3.2-p6/petsc-arch/bin/mpiexec'
    
    $petsc myexecutable
    
  3. Use a function in your script. Probably better if petsc is complex

    function petsc () {
        command 1
        command 2
    }
    
    petsc myexecutable
    
  4. Source your aliases

    shopt -s expand_aliases
    source /home/your_user/.bashrc
    

You probably do not want to source your .bashrc, so, IMO, one of the first 3 would be better.

  • 11
    Point 4 don't work, unless you use shopt -s expand_aliases in the same script. – enzotib Jan 26 '12 at 18:29
  • Your suggestion 2) works, but I want to be able to use the same command in multiple shell scripts without having to write the first line petsc="...". Is there a way to do this? – Paul Jan 26 '12 at 18:31
  • Sounds as if you should put the command in a more standard location, such as /usr/local/bin – Panther Jan 26 '12 at 18:35
  • 1
    @enzotib - thank you, I added that to my answer. – Panther Jan 26 '12 at 18:36
  • 1
    In the point 2 you do not set an alias but a variable. – pabouk Nov 1 '14 at 9:58

Aliases are deprecated in favor of shell functions. From the bash manual page:

For almost every purpose, aliases are superseded by shell functions.

To create a function, and export it to subshells, put the following in your ~/.bashrc:

petsc() {
    ~/petsc-3.2-p6/petsc-arch/bin/mpiexec "$@"
}
export -f petsc

Then you can freely call your command from your scripts.

  • That almost works... the only problem is that I need to be able to pass different flags to the executable "mpiexec"... For instance, I need to be able to execute something like "petsc -n 40 myexecutable" with the alias "petsc" – Paul Jan 26 '12 at 18:46
  • 3
    @Paul: I added "$@" just to handle arguments. – enzotib Jan 26 '12 at 19:47

Shell functions and aliases are limited to the shell and do not work in executed shell scripts. Alternatives for your case:

  • (if you do not bother to use mpiexec instead of petsc) Add $HOME/petsc-3.2-p6/petsc-arch/bin to your PATH variable. This can be done by editing ~/.profile and appending:

    PATH="$HOME/petsc-3.2-p6/petsc-arch/bin:$PATH"
    

    Re-login to apply these changes

  • Create the directory ~/bin and

    • make a wrapper script named petsc containing:

      #!/bin/sh
      exec ~/petsc-3.2-p6/petsc-arch/bin/mpiexec "$@"
      
    • if the program allows for it, you can skip the shellscript and make a symlink using the command:

      ln -s ~/petsc-3.2-p6/petsc-arch/bin/mpiexec ~/bin/petsc
      

In bash 4 you can use special variable: $BASH_ALIASES.

For example:

$ alias foo="echo test"
$ echo ${BASH_ALIASES[foo]}
echo test
$ echo `${BASH_ALIASES[foo]}` bar
test bar

Alternatively define as variable then use command substitution or eval.

So for example, instead of defining the alias such as:

alias foo="echo test"

define it as:

foo="echo test"

instead. Then execute it by either:

find . -type f -exec sh -c "eval $foo" \;

or:

find . -type f -exec sh -c "echo `$foo`" \;
  • Altough aliases are deprecated in favor of shell functions, this answer os the only one which should be accepted. Even the old Debian 8 has version 4 of bash, so the ${BASH_ALIASES[alias]} is a nice option. Otherwise i had to edit lot of lines of my .bash_aliases to apply other things. Thank you. – erm3nda Sep 16 '17 at 9:23

You can force bash to execute your script as an interactive shell with the -i flag. This will tell your .bashrc file to define aliases and other functions.

Example:

~ $ grep ll .bashrc
alias ll='ls -lah'
~ $ cat script.sh 
#!/bin/sh

ll
~ $ bash script.sh 
script.sh: line 3: ll: command not found
~ $ bash -i script.sh
..directory contents..

More info:

$ man bash
  • 2
    .bashrc is also read during non-interactive SSH command execution (that's why it has a check for interactivity at the top) – muru Jan 10 '17 at 13:12
  • I have edited my answer. Thanks @muru – Amado Martinez Jan 10 '17 at 23:10
  1. In .bash_aliases:

    petsc { ~/petsc-3.2-p6/petsc-arch/bin/mpiexec "$@" }

Or put the function in .bashrc if you call it often. Be told that in .bashrc only config settings of bash is stored.

  1. In Terminal: source .bash_aliases
  2. petsc arg(s)

Advantage: you do not need export -f petscin .bash_aliases. Aliases are deprecated but I suppose using .bash_aliases is not.

  • I like this solution, I will give it a try later – Greenonline Apr 24 '15 at 2:24
  1. Use your aliases in your shell script.
  2. Source your script in your current, interactive shell instead of executing it.

So if you have a file called script.sh with your commands that include using aliases, simply type:

source script.sh
  • @DavidFoerster This method works fine. Sourcing a script with the . or source buiiltin causes the current shell to execute all the commands in it. If alias expansion would occur in the shell in which . or source is run, it occurs. However, it's important to realize that this method is only sometimes useful, because often one needs or wants to execute a script in its own shell, with its own environment. Shell scripts written with the intention of being executed in the usual way should not usually be sourced instead--they often won't work right. – Eliah Kagan Jan 10 '17 at 9:44
  • @EliahKagan: Thanks. Now I understand what the answer is supposed to mean. I'll add an explanation. – David Foerster Jan 10 '17 at 9:52
ALIASES
   ...
   Aliases are not expanded when the shell is not interactive, unless the expand_aliases shell option is set using shopt (see the description of shopt under SHELL BUILTIN COMMANDS
   below).

So the real answer to this question, for those looking to use actual aliases in shell scripts instead of alternatives to them, is:

#!/bin/bash

shopt -s expand_aliases

alias foo=bar

foo whatever

As for why I'd want to do this: Due to unusual circumstances, I need to trick a Dockerfile into thinking it's a shell script.

(EDIT: removed functions since I misread calling of mpiexec.)

If the only thing you need is less typing, why don't you just put the folder in $PATH? Or make a symlink to mpiexec from some folder in $PATH? Or (my favourite) put the alias in a script that you source in the calling script?

  • The reason why I can't put it into my $PATH is because I have another 'mpiexec' file in another directory that is alredy in my $PATH. If I add the path to this new 'mpiexec', it will probably try to execute both of them... wouldn't it? – Paul Jan 26 '12 at 19:34
  • 1
    Cannot understand why not simply use "$@". – enzotib Jan 26 '12 at 19:49
  • 2
    Paul, it'll try to execute the one that's first in the PATH, not both. – unhammer Jan 27 '12 at 9:41
  • enzotib, ah I misread the way mpiexec was called, I thought it needed all args as one. Will edit my answer :) – unhammer Jan 27 '12 at 9:44

Your Answer

 

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Not the answer you're looking for? Browse other questions tagged or ask your own question.