Make a Bash alias that takes a parameter

Question

I used to use CShell  csh   which lets you make an alias that takes a parameter  The notation was something like  alias junk  mv         Trash    In Bash  this does not seem to work  Given that Bash has a multitude of useful features  I would assume that this one has been implemented but I am wondering how

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Once i did some fun project and i still use it. It's showing some animation while i copy files via cp command coz cp don't show anything and it's kind of frustrating. So i made this alias

alias cp="~/SCR/spiner cp"

And this is the spiner script

#!/bin/bash

#Set timer
T=$(date +%s)

#Add some color
. ~/SCR/color

#Animation sprites
sprite=( "(* )  ( *)" " (* )( *) " " ( *)(* ) " "( *)  (* )" "(* )  ( *)" )

#Print empty line and hide cursor
printf "\n${COF}"

#Exit function
function bye { printf "${CON}"; [ -e /proc/$pid ] && kill -9 $pid; exit; }; trap bye INT

#Run our command and get its pid
"$@" & pid=$!

#Waiting animation
i=0; while [ -e /proc/$pid ]; do sleep 0.1

    printf "\r${GRN}Please wait... ${YLW}${sprite[$i]}${DEF}"
    ((i++)); [[ $i = ${#sprite[@]} ]] && i=0

done

#Print time and exit
T=$(($(date +%s)-$T))
printf "\n\nTime taken: $(date -u -d @${T} +'%T')\n"

bye

It's look like this

Cycled animation)

Here is the link to a color script mentioned above. And new animation cycle)

User · Answer

Syntax  alias shortName  quot your custom command here quot   Example  alias tlogs   t logs     tail -f    path  1 to project logs txt      t logs

User · Answer

Bash alias does not directly accept parameters  You will have to create a function   alias does not accept parameters but a function can be called just like an alias  For example   myfunction          do things with parameters like  1 such as     mv   1    1 bak      cp   2    1      myfunction old conf new conf  calls  myfunction    By the way  Bash functions defined in your  bashrc and other files are available as commands within your shell  So for instance you can call the earlier function like this     myfunction original conf my conf

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Respectfully to all those saying you can t insert a parameter in the middle of an alias I just tested it and found that it did work  alias mycommand    quot python3  quot  1 quot  script py --folderoutput RESULTS  quot   when I then ran mycommand foobar  it worked exactly as if I had typed the command out longhand

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NB  In case the idea isn t obvious  it is a bad idea to use aliases for anything but aliases  the first one being the  function in an alias  and the second one being the  hard to read redirect source   Also  there are flaws  which i thought would be obvious  but just in case you are confused  I do not mean them to actually be used    anywhere                                                                                                                                                      I ve answered this before  and it has always been like this in the past   alias foo    foo     unset -f  0  echo  arg1 for foo  1        foo      which is fine and good  unless you are avoiding the use of functions all together  in which case you can take advantage of bash s vast ability to redirect text   alias bar  cat  lt  lt  lt      echo arg1 for bar  1       source  dev stdin    They are both about the same length give or take a few characters    The real kicker is the time difference  the top being the  function method  and the bottom being the  redirect-source  method  To prove this theory  the timing speaks for itself   arg1 for foo FOOVALUE  real 0m0 011s user 0m0 004s sys 0m0 008s     lt --time spent in foo  real 0m0 000s user 0m0 000s sys 0m0 000s     lt --time spent in bar arg1 for bar BARVALUE ubuntu localhost  usr bin  time foo FOOVALUE  time bar BARVALUE arg1 for foo FOOVALUE  real 0m0 010s user 0m0 004s sys 0m0 004s  real 0m0 000s user 0m0 000s sys 0m0 000s arg1 for bar BARVALUE ubuntu localhost  usr bin  time foo FOOVALUE  time bar BARVALUE arg1 for foo FOOVALUE  real 0m0 011s user 0m0 000s sys 0m0 012s  real 0m0 000s user 0m0 000s sys 0m0 000s arg1 for bar BARVALUE ubuntu localhost  usr bin  time foo FOOVALUE  time bar BARVALUE arg1 for foo FOOVALUE  real 0m0 012s user 0m0 004s sys 0m0 004s  real 0m0 000s user 0m0 000s sys 0m0 000s arg1 for bar BARVALUE ubuntu localhost  usr bin  time foo FOOVALUE  time bar BARVALUE arg1 for foo FOOVALUE  real 0m0 010s user 0m0 008s sys 0m0 004s  real 0m0 000s user 0m0 000s sys 0m0 000s arg1 for bar BARVALUE   This is the bottom part of about 200 results  done at random intervals  It seems that function creation destruction takes more time than redirection  Hopefully this will help future visitors to this question  didn t want to keep it to myself

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An alternative solution is to use marker  a tool I ve created recently that allows you to  bookmark  command templates and easily place cursor at command place-holders       I found that most of time  I m using shell functions so I don t have to write frequently used commands again and again in the command-line  The issue of using functions for this use case  is adding new terms to my command vocabulary and having to remember what functions parameters refer to in the real-command  Marker goal is to eliminate that mental burden

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Both functions and aliases can use parameters as others have shown here  Additionally  I would like to point out a couple of other aspects   1  function runs in its own scope  alias shares scope  It may be useful to know this difference in cases you need to hide or expose something  It also suggests that a function is the better choice for encapsulation      function tfunc        GlobalFromFunc  Global From Func    Function set global variable by default     local FromFunc  onetwothree from func    Set a local variable     alias talias  local LocalFromAlias  Local from Alias    GlobalFromAlias  Global From Alias    Cant hide a variable with local here     Test variables set by tfunc tfunc   call tfunc echo  GlobalFromFunc   This is visible echo  LocalFromFunc   This is not visible   Test variables set by talias   call talias talias echo  GlobalFromAlias   This is invisible echo  LocalFromAlias   This variable is unset and unusable    Output   bash-3 2        Test variables set by tfunc bash-3 2      tfunc   call tfunc bash-3 2      echo  GlobalFromFunc   This is visible Global From Func bash-3 2      echo  LocalFromFunc   This is not visible  bash-3 2        Test variables set by talias bash-3 2        call talias bash-3 2      talias bash  local  can only be used in a function bash-3 2      echo  GlobalFromAlias   This is invisible Global From Alias bash-3 2  echo  LocalFromAlias   This variable is unset and unusable   2  wrapper script is a better choice  It has happened to me several times that an alias or function can not be found when logging in via ssh or involving switching usernames or multi-user environment  There are tips and tricks with sourcing dot files  or this interesting one with alias  alias sd  sudo   lets this subsequent alias alias install  sd apt-get install  work as expect  notice the extra space in sd  sudo      However  a wrapper script works better than a function or alias in cases like this  The main advantage with a wrapper script is that it is visible executable for under intended path  i e   usr loca bin   where as a function alias needs to be sourced before it is usable  For example  you put a function in a    bash profile or    bashrc for bash  but later switch to another shell  i e  zsh  then the function is not visible anymore   So  when you are in doubt  a wrapper script is always the most reliable and portable solution

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Refining the answer above  you can get 1-line syntax like you can for aliases  which is more convenient for ad-hoc definitions in a shell or  bashrc files   bash  myfunction     mv   1    1 bak   amp  amp  cp -i   2    1      bash  myfunction original conf my conf   Don t forget the semi-colon before the closing right-bracket  Similarly  for the actual question   csh  alias junk  mv         Trash   bash  junk     mv         Trash       Or   bash  junk     for item in        do echo  Trashing   item    mv   item     Trash   done

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The question is simply asked wrong   You don t make an alias that takes parameters because alias just adds a second name for something that already exists   The functionality the OP wants is the function command to create a new function   You do not need to alias the function as the function already has a name   I think you want something like this    function trash     mv         Trash      That s it   You can use parameters  1   2   3  etc  or just stuff them all with

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Here s the example   alias gcommit  function  f     git add -A  git commit -m   1        f    Very important    There is a space after   and before    There is a   after each command in sequence  If you forget this after the last command  you will see  gt  prompt instead  The argument is enclosed in quotes as   1

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To give specific answer to the Question posed about creating the alias to move the files to Trash folder instead of deleting them  alias rm  quot mv  quot  1 quot  -t    Trash  quot   Offcourse you have to create dir    Trash first  Then just give following command   rm  lt filename gt   rm  lt dirname gt

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There are legitimate technical reasons to want a generalized solution to the problem of bash alias not having a mechanism to take a reposition arbitrary arguments   One reason is if the command you wish to execute would be adversely affected by the changes to the environment that result from executing a function   In all other cases  functions should be used   What recently compelled me to attempt a solution to this is that I wanted to create some abbreviated commands for printing the definitions of variables and functions   So I wrote some functions for that purpose   However  there are certain variables which are  or may be  changed by a function call itself   Among them are   FUNCNAME BASH SOURCE BASH LINENO BASH ARGC BASH ARGV  The basic command I had been using  in a function  to print variable defns  in the form output by the set command was   sv      set   grep --color never --    1          E g     gt  V voodoo sv V V voodoo   Problem   This won t print the definitions of the variables mentioned above as they are in the current context  e g   if in an interactive shell prompt  or not in any function calls   FUNCNAME isn t defined   But my function tells me the wrong information    gt  sv FUNCNAME FUNCNAME   0   sv     One solution I came up with has been mentioned by others in other posts on this topic   For this specific command to print variable defns   and which requires only one argument  I did this   alias asv   grep --     cat -       lt  set    lt  lt  lt     Which gives the correct output  none   and result status  false     gt  asv FUNCNAME  gt  echo    1   However  I still felt compelled to find a solution that works for arbitrary numbers of arguments   A General Solution To Passing Arbitrary Arguments To A Bash Aliased Command      I put this code in a file  alias-arg sh       cmd  arg1          an experimental command that optionally takes args    which are printed as  cmd arg1           Also sets global variable  CMD DONE  to  true     cmd      echo  cmd       declare -g CMD DONE true       Now set up an alias  ac2  that passes to cmd two arguments placed   after the alias  but passes them to cmd with their order reversed      ac2 cmd arg2 cmd arg1     calls  cmd  as   cmd cmd arg1 cmd arg2    alias ac2         Set up cmd to be execed after f   finishes            trap     cmd    CMD ARGV 1       CMD ARGV 0        SIGUSR1                                                                   This is the actually execed command               f  arg0 arg1          acquires args and sets up trap to run cmd      f              declare -ag CMD ARGV            array to give args to cmd         kill -SIGUSR1                   this causes cmd to be run         trap SIGUSR1                    unset the trap for SIGUSR1         unset CMD ARGV                  clean up env            unset f                         incl  this function             f     Finally  exec f  which will receive the args following  ac2     E g     gt    alias-arg sh  gt  ac2 one two cmd two one   gt   gt    Check to see that command run via trap affects this environment   gt  asv CMD DONE CMD DONE true   A nice thing about this solution is that all the special tricks used to handle positional parameters  arguments  to commands will work when composing the trapped command   The only difference is that array syntax must be used   E g    If you want       use    CMD ARGV        If you want       use     CMD ARGV        Etc

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As has already been pointed out by others  using a function should be considered best practice   However  here is another approach  leveraging xargs   alias junk  xargs -I      -- mv          Trash   lt  lt  lt      Note that this has side effects regarding redirection of streams

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You don t have to do anything  alias does this automatically   For example  if i want to make git pull origin master parameterized  i can simply create an alias as follows   alias gpull    git pull origin     and when actually calling it  you can pass  master   the branch name  as a parameter  like this   gpull master   or any other branch gpull mybranch

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Functions are indeed almost always the answer as already amply contributed and confirmed by this quote from the man page   For almost every purpose  aliases are superseded by shell functions    For completeness and because this can be useful  marginally more lightweight syntax  it could be noted that when the parameter s  follow the alias  they can still be used  although this wouldn t address the OP s requirement    This is probably easiest to demonstrate with an example   alias ssh disc  ssh -O stop    allows me to type smth like ssh disc myhost  which gets expanded as expected as  ssh -O stop myhost   This can be useful for commands which take complex arguments  my memory isn t what it use t be anymore

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For taking parameters  you should use functions   However    get interpreted when creating the alias instead of during the execution of the alias and escaping the   doesn   t work either  How do I solve this problem   You need to use shell function instead of an alias to get rid of this problem  You can define foo as follows   function foo      path to command           OR  foo      path to command           Finally  call your foo   using the following syntax   foo arg1 arg2 argN   Make sure you add your foo   to    bash profile or    zshrc file   In your case  this will work  function trash     mv       Trash

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If you re looking for a generic way to apply all params to a function  not just one or two or some other hardcoded amount  you can do that this way      usr bin env bash    you would want to  source  this file  maybe in your  bash profile  function runjar fn        java -jar myjar jar          alias runjar runjar fn    So in the example above  i pass all parameters from when i run runjar to the alias   For example  if i did runjar hi there it would end up actually running java -jar myjar jar hi there  If i did runjar one two three it would  run java -jar myjar jar one two three   I like this    - based solution because it works with any number of params

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TL DR  Do this instead  Its far easier and more readable  to use a function than an alias to put arguments in the middle of a command      wrap args     echo  before    after       wrap args 1 2 3 before 1 2 3 after   If you read on  you ll learn things that you don t need to know about shell argument processing  Knowledge is dangerous  Just get the outcome you want  before the dark side forever controls your destiny   Clarification  bash aliases do accept arguments  but only at the end     alias speak echo   speak hello world hello world   Putting arguments into the middle of command via alias is indeed possible but it gets ugly   Don t try this at home  kiddies   If you like circumventing limitations and doing what others say is impossible  here s the recipe  Just don t blame me if your hair gets frazzled and your face ends up covered in soot mad-scientist-style   The workaround is to pass the arguments that alias accepts only at the end to a wrapper that will insert them in the middle and then execute your command   Solution 1  If you re really against using a function per se  you can use     alias wrap args  f    echo before      after   unset -f f     f    wrap args x y z before x y z after   You can replace    with  1 if you only want the first argument   Explanation 1  This creates a temporary function f  which is passed the arguments  note that f is called at the very end   The unset -f removes the function definition as the alias is executed so it doesn t hang around afterwards   Solution 2  You can also use a subshell     alias wrap args  sh -c     echo before      after          Explanation 2  The alias builds a command like   sh -c  echo before      after      Comments     The placeholder   is required  but it could be anything  It gets set to sh s  0  and is required so that the first of the user-given arguments don t get consumed  Demonstration   sh -c  echo Consumed    0  Printing        alcohol drunken babble Consumed  alcohol Printing  drunken babble  The single-quotes inside single-quotes are required  Here s an example of it not working with double quotes     sh -c  echo Consumed   0 Printing      alcohol drunken babble Consumed  -bash Printing    Here the values of the interactive shell s  0 and    are replaced into the double quoted before it is passed to sh  Here s proof   echo  Consumed   0 Printing      Consumed  -bash Printing    The single quotes ensure that these variables are not interpreted by interactive shell  and are passed literally to sh -c   You could use double-quotes and      but best practice is to quote your arguments  as they may contain spaces   and         looks even uglier  but may help you win an obfuscation contest where frazzled hair is a prerequisite for entry

User · Answer

Bash alias absolutely does accept parameters  I just added an alias to create a new react app which accepts the app name as a parameter  Here s my process   Open the bash profile for editing in nano  nano   bash profile   Add your aliases  one per line   alias gita  git add    alias gitc  git commit -m       alias gitpom  git push origin master  alias creact  npx create-react-app            note  the      accepts parameters passed in like  creact my-new-app    Save and exit nano editor     ctrl o to to write  hit enter   ctrl x to exit    Tell terminal to use the new aliases in  bash profile  source   bash profile   That s it  You can now use your new aliases

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Here s are three examples of functions I have in my    bashrc  that are essentially aliases that accept a parameter    Utility required by all below functions   https   stackoverflow com questions 369758 how-to-trim-whitespace-from-bash-variable comment21953456 3232433 alias trim  sed -e  s     space      g  -e  s    space        g          lt  lt COMMENT     Alias function for recursive deletion  with are-you-sure prompt       Example          srf  home myusername django files rest tutorial rest venv       Parameter is required  and must be at least one non-whitespace character       Short description  Stored in SRF DESC      With the following setting  this is  not  added to the history          export HISTIGNORE   rm -r  srf        - https   superuser com questions 232885 can-you-share-wisdom-on-using-histignore-in-bash      See      - y n prompt  https   stackoverflow com a 3232082 2736496     - Alias w param  https   stackoverflow com a 7131683 2736496 COMMENT  SRF DESC  For  aliaf  command  with an  f    Must end with a newline  SRF DESC  srf  path   Recursive deletion  with y n prompt n  srf           Exit if no parameter is provided  if it s the empty string          param   echo   1    trim          echo   param          if   -z   param      http   tldp org LDP abs html comparison-ops html         then           echo  Required parameter missing  Cancelled   return         fi       Actual line-breaks required in order to expand the variable       - https   stackoverflow com a 4296147 2736496     read -r -p  About to     sudo rm -rf    param   Are you sure   y N    response     response   response         tolower     if     response      yes y          then         sudo rm -rf   param      else         echo  Cancelled       fi          lt  lt COMMENT     Delete item from history based on its line number  No prompt       Short description  Stored in HX DESC      Examples         hx 112         hx 3      See      - https   unix stackexchange com questions 57924 how-to-delete-commands-in-history-matching-a-given-string COMMENT  HX DESC  For  aliaf  command  with an  f    Must end with a newline  HX DESC  hx  linenum   Delete history item at line number n  hx          history -d   1           lt  lt COMMENT     Deletes all lines from the history that match a search string  with a     prompt  The history file is then reloaded into memory       Short description  Stored in HXF DESC      Examples         hxf  rm -rf          hxf  source      Parameter is required  and must be at least one non-whitespace character       With the following setting  this is  not  added to the history          export HISTIGNORE   hxf        - https   superuser com questions 232885 can-you-share-wisdom-on-using-histignore-in-bash      See      - https   unix stackexchange com questions 57924 how-to-delete-commands-in-history-matching-a-given-string COMMENT  HXF DESC  For  aliaf  command  with an  f    Must end with a newline  HXF DESC  hxf  searchterm   Delete all history items matching search term  with y n prompt n  hxf           Exit if no parameter is provided  if it s the empty string          param   echo   1    trim          echo   param          if   -z   param      http   tldp org LDP abs html comparison-ops html         then           echo  Required parameter missing  Cancelled   return         fi      read -r -p  About to delete all items from history that match    param    Are you sure   y N    response     response   response         tolower     if     response      yes y          then          Delete all matched items from the file  and duplicate it to a temp          location          grep -v   param    HISTFILE   gt   tmp history           Clear all items in the current sessions history  in memory   This          empties out  HISTFILE          history -c           Overwrite the actual history file with the temp one          mv  tmp history   HISTFILE            Now reload it          history -r   HISTFILE       Alternative  exec bash     else         echo  Cancelled       fi     References    Trimming whitespace from strings  How to trim whitespace from a Bash variable  Actual line breaks  https   stackoverflow com a 4296147 2736496 Alias w param  https   stackoverflow com a 7131683 2736496   another answer in this question  HISTIGNORE  https   superuser com questions 232885 can-you-share-wisdom-on-using-histignore-in-bash Y N prompt  https   stackoverflow com a 3232082 2736496 Delete all matching items from history  https   unix stackexchange com questions 57924 how-to-delete-commands-in-history-matching-a-given-string Is string null empty  http   tldp org LDP abs html comparison-ops html

User · Answer

Here is another approach using read  I am using this for brute search of a file by its name fragment  ignoring the  quot permission denied quot  messages  alias loc0    IFS  read -r x  find   -iname  quot   quot  -print 2 gt  dev null   grep  x    lt  lt  lt    A simple example      IFS  read -r x  echo  quot 1  x 2  quot     lt  lt  lt   quot a b quot  1 a b 2   Note  that this converts the argument as a string into variable s   One could use several parameters within quotes for this  space separated      read -r x0 x1  echo  quot 1   x0  2   x1  3  quot     lt  lt  lt   quot a b quot  1 a 2 b 3

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I will just post my  hopefully  okay  solution  for future readers   amp  most vitally  editors   So - please edit  amp  improve  or remove  anything in this post  In the terminal    alias  lt name of your alias gt   argname  quot  lt command gt   argname quot   and to use it    lt name of your alias gt   argname  for example  a alias to cat a file called hello txt    alias name is CAT FILE   and the  f  is the  argname  which is a file in this example     alias CAT FILE  f  quot cat  f quot     echo  quot   quot   gt  gt  hello txt   echo  quot hello there  quot   gt  gt  hello txt   echo  quot   quot   gt  gt  hello txt   cat hello txt      hello there   Test  CAT FILE  hello txt

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All you have to do is make a function inside an alias    alias mkcd   mkcd    mkdir  quot  1 quot   cd  quot  1 quot      mkcd                                                        You must put double quotes around  quot  1 quot  because single quotes will not work  This is because clashing the quotes at the places marked with arrows confuses the system  Also  a space at the place marked with a star is needed for the function

[bash] Make a Bash alias that takes a parameter?

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