Text snippet creator/manager in Bash

Question

Below is a script to create and manage text snippets. It is also posted on GitHub. Most of the code is error checking and displaying help because I wanted to make a solid command line interface. The blanks function is used when copying a snippet with a blank (@) character in it. The user fills in the blanks.

I am looking for a review of the script: Is it easy to use? Is the code confusing? Are there any horrible bugs that I left unnoticed?

It is tested in OS X, so I am not sure if the syntax will work elsewhere. Specifically, the pbcopy and pbpaste aliases are untested.

#!/bin/sh
list() {
 echo "snp snippets:\n"
 echo "$(ls -R $snippets_dir)"
}
move() {
 if [[ "2ドル" == "" && 3ドル == "" ]]; then
 echo "snp usage:\n"
 echo "snp move <name> <group>"
 elif [[ -e $snippets_dir/2ドル ]]; then
 if -d $snippets_dir/3ドル ]]; then
 mv $snippets_dir/2ドル $snippets_dir/3ドル/2ドル
 else
 echo "ERROR: Group $snippets_dir/3ドル does not exist."; exit 1
 fi
 else
 echo "ERROR: Snippet 2ドル does not exist."; exit 1
 fi
}
new() {
 if [[ "2ドル" == "" && "3ドル" == "" ]]; then
 echo "snp usage:\n"
 echo "snp new <name> \"<text>\""
 echo "snp new group <name>"
 elif [[ "2ドル" == "group" || "2ドル" == "g" ]]; then # New group
 if [[ "3ドル" != "" ]]; then
 mkdir $snippets_dir/3ドル
 echo "Created new group \"3ドル\"."
 else
 echo "snp usage:\n"
 echo "snp new group <name>"
 fi
 else # New snippet
 if [[ "2ドル" == "" ]]; then
 echo "snp usage:\n"
 echo "snp new <name> \"<text>\""
 else
 if [[ -e $snippets_dir/2ドル ]]; then
 echo "Snippet $snippet_dir/2ドル already exists."
 echo "Overwrite? [y/n]"
 read yn
 if [[ $yn == "y" || $yn == "Y" ]]; then
 rm $snippets_dir/2ドル
 else
 return
 fi
 fi
 printf "3ドル" >> $snippets_dir/2ドル
 echo "Created new snippet \"2ドル\"."
 fi
 fi
}
remove() {
 if [[ "2ドル" == "" ]]; then
 echo "snp usage:\n"
 echo "snp remove <name>"
 echo "snp remove group <name>"
 elif [[ "2ドル" == "group" || "2ドル" == "g" ]]; then # Remove group
 if [[ "3ドル" != "" ]]; then
 if [[ -e "$snippets_dir/3ドル" ]]; then
 rm -rf $snippets_dir/3ドル
 echo "Removed group \"3ドル\"."
 else
 echo "ERROR: Group 3ドル does not exist."; exit 1
 fi
 else
 echo "snp usage:\n"
 echo "snp remove group <name>"
 fi
 elif [[ "2ドル" != "" ]]; then # Remove snippet
 if [[ -e $snippets_dir/2ドル ]]; then
 rm $snippets_dir/2ドル
 echo "Removed snippet \"2ドル\"."
 else
 echo "ERROR: Snippet 2ドル does not exist."; exit 1
 fi
 fi
}
blanks() {
 data=$(cat 1ドル)
 count=0
 OIFS=$IFS
 IFS="@"
 blanx=$(echo "$data" | tr -d -c '@' | wc -c | awk '{print 1ドル}')
 result=""
 for x in $data; do
 if [ $count -eq $blanx ]; then
 echo "$x"
 result="$result$x"
 break
 fi
 echo "$x"
 result="$result$x"
 read -p"snp> " v
 result="$result$v"
 count=`expr $count + 1`
 done
 IFS=$OIFS
 printf "$result" >> 1ドル-tmp
}
copy() {
 if [[ "1ドル" == "" ]]; then
 usage
 elif [[ -e $snippets_dir/1ドル ]]; then
 if [ ! $(uname -s) = "Darwin" ]; then
 alias pbcopy='xsel --clipboard --input'
 fi
 blanks $snippets_dir/1ドル
 cat $snippets_dir/1ドル-tmp | pbcopy
 echo "Snippet text copied to clipboard."
 rm $snippets_dir/1ドル-tmp
 else
 echo "ERROR: Snippet 1ドル does not exist."; exit 1
 fi
}
paste() {
 if [[ "2ドル" == "" ]]; then
 usage
 elif [[ -e $snippets_dir/2ドル ]]; then
 if [ ! $(uname -s) = "Darwin" ]; then
 alias pbcopy='xsel --clipboard --input'
 alias pbpaste='xsel --clipboard --output'
 fi
 blanks $snippets_dir/2ドル
 cat $snippets_dir/2ドル-tmp | pbcopy
 pbpaste
 rm $snippets_dir/2ドル-tmp
 else
 echo "ERROR: Snippet 2ドル does not exist."; exit 1
 fi
}
usage() {
 echo "snp usage:\n"
 echo "snp <name> # Copy snippet to clipboard"
 echo "snp paste <name> # Paste name (from clipboard)"
 echo "snp new <name> \"<text>\" # New snippet"
 echo "snp new group <name> # New group"
 echo "snp list # List snippets"
 echo "snp move <name> <group> # Move snippet to group"
 echo "snp remove <name> # Remove snippet"
 echo "snp remove group <name> # Remove group"
 echo "snp help # Display usage"
}
snippets_dir=~/".snp"
# Check for/create snippet dir
if [[ ! -d $snippets_dir ]]; then
 echo "ERROR: $snippets_dir doesn't exist."
 echo "Create it now? [y/n]"
 read yn
 if [[ $yn == "y" || $yn == "Y" ]]; then
 mkdir $snippets_dir
 echo "$snippets_dir created"
 else
 exit 0
 fi
fi
case 1ドル in
 p|paste)
 paste "$@" ;;
 n|new)
 new "$@" ;;
 l|list)
 list ;;
 m|move)
 move "$@" ;;
 r|remove)
 remove "$@" ;;
 h|help)
 usage ;;
 *)
 copy "$@" ;;
esac
exit 0

Answer 1

Overall

• You're using some bash-specific things ([[ ... && ... ]]), so your shebang line should be #!/bin/bash
• very good indentation, readable code
• more quotes: mv "$snippets_dir/2ドル" "$snippets_dir/3ドル/2ドル"

list function

• ls knows how to print to the screen, don't need echo $(ls ...)

move function

• you need echo -e if you want \n to be interpreted as a newline.
• syntax error on 2nd if, missing [[

new function

• if you use outer single quotes, don't need to escape inner double quotes (unless you need variable interpolation, of course)
• I would test for "yes" like this: if [[ ${yn,} == y* ]] -- see http://www.gnu.org/software/bash/manual/bashref.html#Shell-Parameter-Expansion

blanks function

• declare local variables with local
• to read content from a file in bash: data=$(< "1ドル")
• bash can do arithmetic: (( count++ )) -- see http://www.gnu.org/software/bash/manual/bashref.html#Conditional-Constructs

• you only ever use this function to copy stuff to the clipboard, so you don't need a temp file:

  blanks "$snippets_dir/1ドル" | pbcopy
  

• don't use printf "$astring" -- if $astring contains %-directives you'll get "not enough arguments" errors. Stick to echo, or if you're specifically avoiding a trailing newline, printf "%s" "$astring"

paste function

• I would use case here, if you decide you need OS-specific aliases:

  case $(uname -a) in
   Darwin) : ;;
   *) alias pbcopy='...'
   alias pbpaste='...'
   ;;
  esac
  

• glenn jackman: One more thing I just noticed: the code where you set the pbcopy alias should not be in the copy function, it should be in the "main" scope, or in a setup or config function.

Answer 2

I am not a great fan of fall-through logic ... if there is an argument issue (missing argument, whatever), you are falling through the work functions, and letting the program end. I would make this more explicit with an exit 3. Programs should always set an exit code unless they successfully complete. I don't consider argument errors to be a successful completion.

aside - Bash has some reserved exit codes, which you should typically not use. 1 is one of the reserved exit codes. As a result, try to use values other than 1 or 2 for exit codes from shell scripts....

I would recommend creating an error-handling function... something along the lines of:

generalerror() {
 echo "snp usage:"
 echo 1ドル
 echo
 usage
 exit 3
}
checkargument() {
 if [[ "1ドル" == "" ]]; then
 generalerror 2ドル
 fi
}

This will allow you to centralize a lot of your error handling with some simpler messages/handling... the reason I am suggesting this is because of the following:

remove() {
 if [[ "2ドル" == "" ]]; then
 echo "snp usage:\n"
 echo "snp remove <name>"
 echo "snp remove group <name>"
 elif [[ "2ドル" == "group" || "2ドル" == "g" ]]; then # Remove group
 if [[ "3ドル" != "" ]]; then
 if [[ -e "$snippets_dir/3ドル" ]]; then
 rm -rf $snippets_dir/3ドル
 echo "Removed group \"3ドル\"."
 else
 echo "ERROR: Group 3ドル does not exist."; exit 1
 fi
 else
 echo "snp usage:\n"
 echo "snp remove group <name>"
 fi

That code does not exit 1.... probably because it was just an oversight... and this is why functions are good ;-)

The above code could be:

remove() {
 checkargument 2ドル "snp remove <name>\nsnp remove group <name>"
 if [[ "2ドル" == "group" || "2ドル" == "g" ]]; then # Remove group
 checkargument 3ドル "snp remove group <name>"
 ....

Right, then your error handling:

cat $snippets_dir/1ドル-tmp | pbcopy

The above line is critical to your program.... but, it does not check for errors.... Did the pbcopy succeed?

So:

• functions to extract common logic are useful....
• exit code set for bad values.
• different exit code for functional problems ... (failed sub-commands)
• error handling!

• adamlazz: Thanks for your answer, this is a very interesting recommendation. I will definitely consider implementing it in the future.