[PATCH] feat: Allow to show selected line

[Eddie Barraco]

An annoying problem was that pass didn't allow to show only some
specific line (generaly the first). In some program configuration, we
had to trick to get the password prompted:

Example:

```
~/.msmtprc
passwordeval   "pass show db/Email/Contact/contact at eddiebarraco.fr | head -1"
```

The problem can be tricked only if el famoso program allow to use
redirections and pipes. In some cases the trick become really annoying...

Example:

```
~/.config/vdirsyncer/config
password.fetch = ["command", "/home/eddie/bin/passfirst", "db/Internet/Nextcloud"]
```

```
~/bin/passfirst
pass show "$1" | head -1
```

I thinked about this problem from some times and I think I got a point.

The qrcode and clip logic seems to be too coupled to the line selection
logic and this generate two problems :
-> We cannot clip and qrcode all the lines
-> we cannot show specific lines

So I tried to seperate both logics with a dedicated parameter (--selected-line|-s)

-c and -q will both use selected lines (all the lines if unspecified)
-s will allow to select a specific line (the first line if no line number is used)

Here is a proof of concept and I need reviews to make it better.

The changes will breaks old logics ! If you previously used '-c 1' or '-q 1', it
will no longer works. You'll have to '-c -s 1' or '-q -s 1'. But the
price is worth IMHO cause we will be able to do more things.

TY dudes, good night.
---
 src/password-store.sh | 28 +++++++++++++++++++---------
 1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/src/password-store.sh b/src/password-store.sh
index 284eabf..1c6c786 100755
--- a/src/password-store.sh
+++ b/src/password-store.sh
@@ -281,7 +281,7 @@ cmd_usage() {
 	        List passwords.
 	    $PROGRAM find pass-names...
 	    	List passwords that match pass-names.
-	    $PROGRAM [show] [--clip[=line-number],-c[line-number]] pass-name
+	    $PROGRAM [show] [--clip,-c | --qrcode,-q] [--selected-line[=line-number],-s[line-number]] pass-name
 	        Show existing password and optionally put it on the clipboard.
 	        If put on the clipboard, it will be cleared in $CLIP_TIME seconds.
 	    $PROGRAM grep [GREPOPTIONS] search-string
@@ -363,17 +363,18 @@ cmd_init() {
 }
 
 cmd_show() {
-	local opts selected_line clip=0 qrcode=0
-	opts="$($GETOPT -o q::c:: -l qrcode::,clip:: -n "$PROGRAM" -- "$@")"
+	local opts selected_line=0 clip=0 qrcode=0
+	opts="$($GETOPT -o q::c::s:: -l qrcode::,clip::,selected-line:: -n "$PROGRAM" -- "$@")"
 	local err=$?
 	eval set -- "$opts"
 	while true; do case $1 in
-		-q|--qrcode) qrcode=1; selected_line="${2:-1}"; shift 2 ;;
-		-c|--clip) clip=1; selected_line="${2:-1}"; shift 2 ;;
+		-q|--qrcode) qrcode=1; shift 2 ;;
+		-c|--clip) clip=1; shift 2 ;;
+		-s|--selected-line) selected_line="${2:-1}"; shift 2 ;;
 		--) shift; break ;;
 	esac done
 
-	[[ $err -ne 0 || ( $qrcode -eq 1 && $clip -eq 1 ) ]] && die "Usage: $PROGRAM $COMMAND [--clip[=line-number],-c[line-number]] [--qrcode[=line-number],-q[line-number]] [pass-name]"
+	[[ $err -ne 0 || ( $qrcode -eq 1 && $clip -eq 1 ) ]] && die "Usage: $PROGRAM $COMMAND [--clip,-c | --qrcode,-q] [--selected-line[=line-number],-s[line-number]] [pass-name]"
 
 	local pass
 	local path="$1"
@@ -381,11 +382,20 @@ cmd_show() {
 	check_sneaky_paths "$path"
 	if [[ -f $passfile ]]; then
 		if [[ $clip -eq 0 && $qrcode -eq 0 ]]; then
-			pass="$($GPG -d "${GPG_OPTS[@]}" "$passfile" | $BASE64)" || exit $?
+			if [[ $selected_line -eq 0 ]]; then
+				pass="$($GPG -d "${GPG_OPTS[@]}" "$passfile" | $BASE64)" || exit $?
+			else
+				[[ $selected_line =~ ^[0-9]+$ ]] || die "Clip location '$selected_line' is not a number."
+				pass="$($GPG -d "${GPG_OPTS[@]}" "$passfile" | tail -n +${selected_line} | head -n 1 | $BASE64)" || exit $?
+			fi
 			echo "$pass" | $BASE64 -d
 		else
-			[[ $selected_line =~ ^[0-9]+$ ]] || die "Clip location '$selected_line' is not a number."
-			pass="$($GPG -d "${GPG_OPTS[@]}" "$passfile" | tail -n +${selected_line} | head -n 1)" || exit $?
+			if [[ $selected_line -eq 0 ]]; then
+				pass="$($GPG -d "${GPG_OPTS[@]}" "$passfile")" || exit $?
+			else
+				[[ $selected_line =~ ^[0-9]+$ ]] || die "Clip location '$selected_line' is not a number."
+				pass="$($GPG -d "${GPG_OPTS[@]}" "$passfile" | tail -n +${selected_line} | head -n 1)" || exit $?
+			fi
 			[[ -n $pass ]] || die "There is no password to put on the clipboard at line ${selected_line}."
 			if [[ $clip -eq 1 ]]; then
 				clip "$pass" "$path"
-- 
2.21.0