[sonic_cli]: Fix bash completion for 'show' command (#355)

files/build_templates/sonic_debian_extension.j2

@@ -70,6 +70,10 @@ sudo dpkg --root=$FILESYSTEM_ROOT -i {{config_engine}}
 sudo dpkg --root=$FILESYSTEM_ROOT -i target/debs/python-sonic-utilities_*.deb || \
     sudo LANG=C DEBIAN_FRONTEND=noninteractive chroot $FILESYSTEM_ROOT apt-get -y install -f
 
+# SONiC utilities installs bash-completion as a dependency. However, it is disabled by default
+# in bash.bashrc, so we copy a version of the file with it enabled here.
+sudo cp -f $IMAGE_CONFIGS/bash/bash.bashrc $FILESYSTEM_ROOT/etc/
+
 # Install SONiC Device Data  (and its dependencies via 'apt-get -y install -f')
 sudo dpkg --root=$FILESYSTEM_ROOT -i target/debs/sonic-device-data_*.deb || \
     sudo LANG=C DEBIAN_FRONTEND=noninteractive chroot $FILESYSTEM_ROOT apt-get -y install -f

files/image_config/bash/bash.bashrc

@@ -0,0 +1,57 @@
+# System-wide .bashrc file for interactive bash(1) shells.
+
+# To enable the settings / commands in this file for login shells as well,
+# this file has to be sourced in /etc/profile.
+
+# If not running interactively, don't do anything
+[ -z "$PS1" ] && return
+
+# check the window size after each command and, if necessary,
+# update the values of LINES and COLUMNS.
+shopt -s checkwinsize
+
+# set variable identifying the chroot you work in (used in the prompt below)
+if [ -z "${debian_chroot:-}" ] && [ -r /etc/debian_chroot ]; then
+    debian_chroot=$(cat /etc/debian_chroot)
+fi
+
+# set a fancy prompt (non-color, overwrite the one in /etc/profile)
+PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '
+
+# Commented out, don't overwrite xterm -T "title" -n "icontitle" by default.
+# If this is an xterm set the title to user@host:dir
+#case "$TERM" in
+#xterm*|rxvt*)
+#    PROMPT_COMMAND='echo -ne "\033]0;${USER}@${HOSTNAME}: ${PWD}\007"'
+#    ;;
+#*)
+#    ;;
+#esac
+
+# enable bash completion in interactive shells
+if ! shopt -oq posix; then
+    if [ -f /usr/share/bash-completion/bash_completion ]; then
+      . /usr/share/bash-completion/bash_completion
+    elif [ -f /etc/bash_completion ]; then
+      . /etc/bash_completion
+    fi
+fi
+
+# if the command-not-found package is installed, use it
+if [ -x /usr/lib/command-not-found -o -x /usr/share/command-not-found/command-not-found ]; then
+    function command_not_found_handle {
+        # check because c-n-f could've been removed in the meantime
+        if [ -x /usr/lib/command-not-found ]; then
+            /usr/lib/command-not-found -- "$1"
+            return $?
+        elif [ -x /usr/share/command-not-found/command-not-found ]; then
+           /usr/share/command-not-found/command-not-found -- "$1"
+           return $?
+        else
+           printf "%s: command not found\n" "$1" >&2
+           return 127
+        fi
+    }
+fi
+
+