问如何用图形对齐git日志

EN

function gitlog
{

   # Check for the existence of certain git log arguments 
   local using_graph=false
   local arg_i
   for arg_i in "$@"
   do 
      if [ "$arg_i" = "--graph" ]; then
         using_graph=true
      fi 
      if [ "$arg_i" = "--oneline" ]; then
         printf -- "--oneline not allowed for this shell function.\n  use regular git log for oneline.\n" 
         return 1
      fi 
   done

   # Set the OS dependant options
   # my_system_type can be set by sourcing my .bashrc
   local sed_regex_sym="r"
   if [ ! -z "$my_system_type" ]; then
      if [ "$my_system_type" = Mac ]; then
         sed_regex_sym="E"
      fi
   fi

   # Set the pre-determined column sizes here
   local N_AUTH_DATE_CHARS=11
   local N_AUTH_NAME_CHARS=15

   # Determine where to place columns for the various content
   local scrn_sz_arr=( $(stty size) )  #stty not tput in case of missing TERMINFO
   local N_SCRN_COLS=${scrn_sz_arr[1]}
   local N_HASH_CHARS=$(git log --pretty=format:%h -1 | tr -d '\n' | wc -c | tr -d '[:space:]')
   if [ "$using_graph" = true ]; then 
      local N_GRPH_MAX_CHARS=$(expr $N_SCRN_COLS / 5) #Use no more then 20% of screen
      local N_GRPH_ACT_CHARS=$(git log --graph --pretty=format:"%<(1,trunc)%ad" | tr -d '..' | \
                               awk '{print length}' | sort -nr | head -1 | tr -d '[:space:]')
      if [ "$N_GRPH_ACT_CHARS" -lt "$N_GRPH_MAX_CHARS" ]; then
         local N_GRPH_RSRV_CHARS=$N_GRPH_ACT_CHARS
      else
         local N_GRPH_RSRV_CHARS=$N_GRPH_MAX_CHARS
      fi
      #Extend space of N_HASH_CHARS to keep alignment when --graph option used.
      N_HASH_CHARS=$(expr $N_HASH_CHARS + $N_GRPH_RSRV_CHARS)
   fi
   local N_MSG_INDENT_CHARS=$(expr $N_HASH_CHARS + 1 + $N_AUTH_DATE_CHARS + $N_AUTH_NAME_CHARS + 1)
   local N_STAT_INDENT_CHARS=$(expr $N_MSG_INDENT_CHARS + 2)

   # Check that there is sufficient room to place all the content
   local N_MIN_COLS=$(expr $N_STAT_INDENT_CHARS + 12)
   if [ "$N_MIN_COLS" -gt "$N_SCRN_COLS" ]; then
      printf -- "Terminal window too narrow.\nNeed at least $N_MIN_COLS cols for this mode.\n"
      return 1
   fi

   # Git log logic below is as follows
   #   - use date=short to minimize space used by that column.  Linked with 
   #        N_AUTH_DATE_CHARS
   #   - use --pretty-format to specify columns as 
   #        hash--author date--author name--commit message.
   #   - first 4 sed statement removes color (if present) from graph lines 
   #        containing wrapped pretty-print text. Done for aligment of wrapped 
   #        text. Was one sed using back references, but that was not compatible
   #        with BSD (OSX) sed with -E.
   #   - fifth sed blanks out graph lines from newlines that were introduced 
   #        between commits by tformat.
   #   - sixth sed aligns wrapped text from pretty-print into message column.
   #   - last three sed statements insert a tab as a delimiter (recall tabs 
   #        removed by expand) between any other text and the --name-status text.
   #        This is in anticipation of the awk statement at the next pipe 
   #   - awk used to right pad the first column up to N_STAT_INDENT_CHARS and
   #        place any --name-status fields present to its right in order to 
   #        align it with the message text.
   #   - use tr to delete the inserted tabs that were used for column alignment
   #   - sed to remove any trailing white space.
   #   - awk removes extraneous blank lines
   #   - finally pipe to less -R to force the color option
   git log \
           --date=short \
           --pretty=tformat:"%C(auto)%w($N_SCRN_COLS,0,$N_MSG_INDENT_CHARS)%>|($N_HASH_CHARS)%h%x09%<($N_AUTH_DATE_CHARS,trunc)%ad%<($N_AUTH_NAME_CHARS,trunc)%an%x09%C(bold blue)%s%C(auto)%+d" \
           $* | \
           expand -t 1 | \
           sed -$sed_regex_sym $'/.*[*]/!{/.*[|]{1}/s/\x1b\\[([0-9](;[0-9])*)*[mGK]([_])\x1b\\[([0-9](;[0-9])*)*[mGK]/_/g;}' | \
           sed -$sed_regex_sym $'/.*[*]/!{/.*[|]{1}/s/\x1b\\[([0-9](;[0-9])*)*[mGK]([|])\x1b\\[([0-9](;[0-9])*)*[mGK]/|/g;}' | \
           sed -$sed_regex_sym $'/.*[*]/!{/.*[|]{1}/s/\x1b\\[([0-9](;[0-9])*)*[mGK]([\\])\x1b\\[([0-9](;[0-9])*)*[mGK]/\\\/g;}' | \
           sed -$sed_regex_sym $'/.*[*]/!{/.*[|]{1}/s/\x1b\\[([0-9](;[0-9])*)*[mGK]([\/])\x1b\\[([0-9](;[0-9])*)*[mGK]/\//g;}' | \
           sed -$sed_regex_sym "/^[|[:space:]]+[^[:alnum:]\\\/]+$/s/[|]//g" | \
           sed -$sed_regex_sym "/^[|]/s/^(.{$N_MSG_INDENT_CHARS})[[:space:]]*/\1/" | \
           sed -$sed_regex_sym "s/^([[:space:]_|\\\/]{0,$N_HASH_CHARS})([A-Z][[:space:]])/\1$(printf -- '\t')\2/" | \
           sed -$sed_regex_sym "s/^([[:space:]_|\\\/]{0,$N_HASH_CHARS})([R][0-9][0-9][0-9][[:space:]])/\1$(printf -- '\t')\2/" | \
           sed -$sed_regex_sym "s/^([[:space:]_|\\\/]{0,$N_HASH_CHARS})([C][0-9][0-9][[:space:]])/\1$(printf -- '\t')\2/" | \
           awk 'BEGIN{ FS="\t" }{ printf "%-'$N_STAT_INDENT_CHARS's%s\n", $1, $2 }' | \
           tr -d '\t' | \
           sed -$sed_regex_sym 's/[[:space:]]*$//' | \
           awk NF | \
           less -R --chop-long-lines
}