How to run an alias in a shell script?
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 aliaspetsc
as a command. After giving my shell script the appropriate permissions (usingchmod
), 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 aliaspetsc
inside the script file? Is there a way I can edit my.bashrc
or.bash_profile
to make this happen?@nitstorm: Neither solution seems to work... I still get the same error as before
I actually just used a system link which worked for me like: `ln -sf /usr/bin/podman .local/bin/docker`
Some options:
In your shell script use the full path rather then an alias.
In your shell script, set a variable, different syntax
petsc='/home/your_user/petsc-3.2-p6/petsc-arch/bin/mpiexec' $petsc myexecutable
Use a function in your script. Probably better if
petsc
is complexfunction petsc () { command 1 command 2 } petsc myexecutable
Source your aliases
shopt -s expand_aliases source /home/your_user/.bashrc
You probably do not want to source your
.bashrc
, so IMO one of the first 3 would be better.Your suggestion 2) works, but I want to be able to use the same command in multiple shell scripts without having to write the first line petsc="...". Is there a way to do this?
Sounds as if you should put the command in a more standard location, such as `/usr/local/bin`
In the point 2 you do not set an alias but a variable.
Not asked for by OP but relevant to the question title: Point 2 won't work with commands containing `|`. Here, use `shopt -s expand_aliases` & local alias, e.g. `alias myalias='echo abc|rev'` - requires line-break before use (see ALIASES in `man bash`). Point 4: Sourced file may prevent non-interactive execution, i.e. in a script. Look for early `exit` or `return`, e.g. `[ -z "$PS1" ] && return` (checks if primary prompt isn't set indicating non-interactive shell) or there may be a check for `i` in `$-` (`$-` contains shell options, `i` means interactive). See `man bash` for those variables.
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 "[email protected]" } 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: I added `"[email protected]"` just to handle arguments.
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 ofpetsc
) Add$HOME/petsc-3.2-p6/petsc-arch/bin
to yourPATH
variable. This can be done by editing~/.profile
and appending:PATH="$HOME/petsc-3.2-p6/petsc-arch/bin:$PATH"
Re-login to apply these changes
Create the directory
~/bin
andmake a wrapper script named
petsc
containing:#!/bin/sh exec ~/petsc-3.2-p6/petsc-arch/bin/mpiexec "[email protected]"
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.
Indeed. In my case, it worked like this: eval ${BASH_ALIASES[foo]} . Even managed to get through nested aliasing, e.g. foo->foo123->/smth/real
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
`.bashrc` is also read during non-interactive SSH command execution (that's why it has a check for interactivity at the top)
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.
In
.bash_aliases
:petsc { ~/petsc-3.2-p6/petsc-arch/bin/mpiexec "[email protected]" }
Or put the function in
.bashrc
. Usually in.bashrc
only config settings ofbash
are stored.In Terminal:
source .bash_aliases
- Call it:
petsc arg(s)
Advantage: you do not need
export -f petsc
in.bash_aliases
. Aliases are deprecated but using.bash_aliases
for functions is ok.I like this solution, I will give it a try later
- Use your aliases in your shell script.
- 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.
@EliahKagan: Thanks. Now I understand what the answer is supposed to mean. I'll add an explanation.
(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?
Cannot understand why not simply use `"[email protected]"`.
Paul, it'll try to execute the one that's first in the PATH, not both.
enzotib, ah I misread the way mpiexec was called, I thought it needed all args as one. Will edit my answer :)
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Content dated before 6/26/2020 9:53 AM
Nitin Venkatesh 9 years ago
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'`