permfunction

permfunction

#!/bin/bash

# This script adds a program/script/command called 'permfunction' to you PATH
# permfunction allows you to write system-wide, on-PATH instantly available, persisted scripts, i.e. improved shell functions/aliases/abbreviations/short programs.
# 
# TODO also persist these functions as gists for the user

# inspired by
# https://askubuntu.com/questions/1414/how-to-create-a-permanent-alias
# https://askubuntu.com/a/80290/521770

#
# installation/update to latest version for current user (this takes precedence over global version, if your PATH is set up as usually):
#
#   curl -s https://gist.githubusercontent.com/Masterxilo/29ac0df083827bbd45a7c8ddcf3936d7/raw/permfunction | bash - ; hash -d permfunction &> /dev/null || true
#
# installation/update of global version for all users (depending on your PATH only this might work out of the box):
#
#   curl -s https://gist.githubusercontent.com/Masterxilo/29ac0df083827bbd45a7c8ddcf3936d7/raw/permfunction | sudo -E bash - ; hash -d permfunction &> /dev/null || true
#
# This last way of installing is required if you want to use sudo permfunction.
#
# uninstall:
#     rm ~/bin/permfunction
#     sudo rm /usr/bin/permfunction

# Note: Installation of the very latest version should be done with a hardlink to the current version /raw/.../functionname instead, because http caching 
# in the gist server makes the /raw/functionname route not always reflect the latest update

set -e
# note that -e only exits immediately if top level error occus - except pipelines  (see below) and sequences (unconditional continuation), expressions are evaluated to completion
set -o pipefail

installdir="/usr/bin" 
! [ -w "$installdir" ] && { installdir="$HOME/bin" ; }
mkdir "$installdir" &> /dev/null || true

file="$installdir/permfunction"
[ -f "$file" ] && { echo >&2 "warning: $file exists, overwriting" ; }
echo "installing permfunction at $file..." ;

which permfunction &> /dev/null && ! [ "`which permfunction`" == "$file" ] && { echo >&2 "error: permfunction is already installed elsewhere at `which permfunction`. Prefer to have one up-to-date installation to avoid version confusion." ; exit 1 ; }

# -------- permfunction source code -----------
cat > "$file" <<'EOF'
#!/bin/bash

set -e
set -o pipefail

[ "$1" == "--redefine" ] && { shift ; redefine=true ; }
[ "$1" == "--file" ] && { shift ; file=true ; }

name="$1"

if [ -z "$redefine" ] ; then
  which "$name" &>/dev/null && { echo "error: command with name $name exists at `which "$name"`. use --redefine to overwrite" ; exit 1 ; } || true # refuse to overwrite/take precedence over existing commands to avoid confusion!
fi

shift || true # shift fails if there are no variables!
code=$(echo "$@") # code is not just $2, but all remaining args, space separated

[ ! -z "$file" ] && { code=$(cat "$code") ; }

FD_NUMBER_STDIN=0 # this is a system constant in linux
if [ -z "$code" ] && [[ -t $FD_NUMBER_STDIN ]] ; then 
  echo >&2 "code is not defined and STDIN is a tty which is not allowed. use 'cat - | permfunction $name' if you want a simple editor. or use 'echo code | permfunction $name'";
  echo ""
  # will display usage below:
else 
  [ -z "$code" ] && {
    code="$(cat /dev/stdin)";
  }
fi

( [ "$name" == "-help" ] || [ "$name" == "-?" ] || [ "$name" == "--?" ] || [ "$name" == "--help" ] || [ -z "$name" ] || [ -z "$code" ] ) && { cat >&2 <<'USAGEEOF'
permfunction allows you to write system-wide, on-PATH instantly available, persisted scripts, i.e. improved shell functions/aliases/abbreviations/short programs.

usage: [sudo] permfunction [--redefine] name code

       [sudo] permfunction [--redefine] name code more-code even-more-code

       [sudo] permfunction [--redefine] name <<'EOF'
       code
       EOF

       [sudo] permfunction [--redefine] name < file_containing_code
       
       -command generating code on stdout- | [sudo] permfunction [--redefine] name
       
       [sudo] permfunction [--redefine] --file name file_containing_code

where stdin cannot be a tty (we don't want to implement any line/terminal editing in this tool).

usage examples:

  permfunction cls "clear"

after this, cls does the same as clear or ctrl+l in any open terminal (with the same PATH)
   
  sudo permfunction cls "clear"

same, but install for all users

  permfunction sayhi 'echo Hello $1'

after this, "sayhi World" prints "Hello World". Note that we cannot let the shell expand $1!!!

   permfunction dosomething '
   echo "this script does"
   echo "something with $1"
   echo "which is so complex that it needs this many lines!!!"
   '
   
after this, try 'dosomething "your shell"', and check out 'cat `which dosomething`'
USAGEEOF

exit 1 ; }

re="[[:space:]]+"
if [[ "$name" =~ $re ]]; then
  echo >&2 "usage: permfunction [--redefine] name code" ;
  echo >&2 "error: name may not contain spaces, was '$name'" ;
  exit 1 ;
fi


installdir="/usr/bin" # system install. requires sudo to write
! [ -w "$installdir" ] && { installdir="$HOME/bin" ; }
mkdir "$installdir" &> /dev/null || true

file="$installdir/$name"

[ -f "$file" ] && [ -z $redefine ] && {
  echo >&2 "error: $file exists. Use --redefine to force overwriting" ;
  [ -w ] && echo >&2 "or use rm $file to delete the existing command manually first";
  ! [ -w ] && echo >&2 "or use sudo rm $file to delete the existing command manually first";
  exit 1 ;
} 
[ -f "$file" ] && ! [ -z $redefine ] && { echo >&2 "warning: $file exists. Redefining." ; } 

echo "$code" > "$file"
chmod +x "$file"

echo "installed $name to $file"
echo "-------------- code listing 'cat $file' ---------------"
cat "$file"
echo "-------------- code listing end ---------------"


! [ "`which $name`" == "$file" ] && { echo >&2 """
error: Installation in PATH failed

  which $name
  
returns 

  `which $name`
  
instead of expected 

  $file
 
Probably '$installdir' is not in your PATH or another program of the same name is taking precedence. If you used [sudo] permfunction, try to use with/without sudo instead.
""" ; exit 1 ; } 

[ "`which $name`" == "$file" ] && { echo "successfully installed $name in PATH, you can now use it" ; }

hash -d $name &> /dev/null || true  # no idea if this helps something/escapes the scope of this script

EOF

chmod +x $file

name="permfunction"
echo "installed $name to $file"

! [ "`which $name`" == "$file" ] && { echo >&2 """
error: Installation in PATH failed

  which $name
  
returns 

  `which $name`
  
instead of expected 

  $file
 
Probably '$installdir' is not in your PATH or another program of the same name is taking precedence. If you used [sudo] permfunction, try to use with/without sudo instead.
"""; exit 1 ; }
[ "`which $name`" == "$file" ] && { echo "successfully installed $name in PATH, you can now use it" ; }

hash -d permfunction &> /dev/null || true  # no idea if this helps something/escapes the scope of this script

it would be cool if I could know what the current revision's url is when installing... maybe using the etag ...

hash -d permfunction to stop permfunction from being searched in the wrong place after reinstallling.

TODO make this persist the functions to a repository
TODO make all functions/scripts this creates self-updating

tested working on ubuntu & WSL (windows subsystem for linux) ubuntu

however, on WSL the PATH is polluted with windows stuff, so only the sudo variant worked - the personal ~/bin dir appears not to be in the PATH.

Here's a command I recently defined (adapted from https://stackoverflow.com/questions/12498304/using-bash-to-display-a-progress-working-indicator https://stackoverflow.com/a/50699733/524504):

permfunction --redefine spinner <<'EOF'
#!/usr/bin/env bash

show_spinner()
{
  local -r pid="${1}"
  local -r delay='0.05'
  local spinstr='\|/-'
  local temp
  while ps a | awk '{print $1}' | grep -q "${pid}"; do
    temp="${spinstr#?}"
    printf " [%c]  " "${spinstr}"
    spinstr=${temp}${spinstr%"${temp}"}
    sleep "${delay}"
    printf "\b\b\b\b\b\b"
  done
  printf "    \b\b\b\b"
}

("$@") &
show_spinner "$!"
EOF

usage:

spinner sleep 5

(known problem: the cursor jumps around and blinks to draw this spinner)

from https://unix.stackexchange.com/questions/225179/display-spinner-while-waiting-for-some-process-to-finish

https://unix.stackexchange.com/a/276558/266802

Recommended aliases:

• define
• pfunction
• persistent_function
• persist

definition using:

permfunction --redefine palias $'name=$1; shift; permfunction $name "$@"\' "$@"\''

# then
palias define permfunction
palias pfunction permfunction
palias persistent_function permfunction
palias persist permfunction

palias persistent_alias palias

nice command: recursive touch/mkdir -p

palias mkdirp 'mkdir -p'

permfunction touchp 'mkdir -p "$(dirname "$1")" && touch "$1" ;'
palias touch2 touchp

https://askubuntu.com/questions/800845/create-file-and-its-parent-directory

touchp test/about/me

find test
tree test

touchp src/main/java/hello/Application.java
for
https://spring.io/guides/gs/testing-web/