Git bash doesn't recognize 'rev' command - bash

Question

I am trying to use a function that shortens my bash prompt. I have added it in .bash_profile:
function last_two_dirs {
pwd |rev| awk -F / '{print $1,$2}' | rev | sed s_\ _/_
}
export PS1='$(last_two_dirs) $(__git_ps1) ➡ '
But I get an error bash: rev: command not found everytime I launch git bash.
I have set the PATH correctly since other commands work correctly except rev. Is rev not part of git bash? Or is there any other way to show only the parent and the current directory for the bash prompt?
OS: Windows 10

Answer 1

Your environment doesn't seem to have the rev command. However, you don't need it, there are built-in facilities for what you want to do.
To get the current working directory in your PS1, use \w:
PS1='\w\$ '
This gets you the full path, so your prompt will look something like
~/tinker/so/subdir/subsubdir$
Now, set the $PROMPT_DIRTRIM variable to the number of trailing directories to retain:
PROMPT_DIRTRIM=2
This will get you a prompt like
~/.../subdir/subsubdir$

Answer 2

This is the code that worked for me -
PROMPT_COMMAND='case $PWD in
$HOME) HPWD="~";;
$HOME/*/*) HPWD="${PWD#"${PWD%/*/*}/"}";;
$HOME/*) HPWD="~/${PWD##*/}";;
/*/*/*) HPWD="${PWD#"${PWD%/*/*}/"}";;
*) HPWD="$PWD";;
esac'
PS1='$HPWD \$'
referred from link

Answer 3

bash function around $PWD
Under bash, there are lot of trick and features you could use to make this a lot quicker and efficient
Simply two last path level:
last_two_dirs() {
local left=${PWD%/*};
echo "${PWD#${left%/*}/}"
}
More complex: first and last level:
path_parts() {
local APATH
IFS=/ read -a APATH <<<"$PWD"
if ((${#APATH[#]}>3)) ;then
echo "/${APATH[1]}..${APATH[-1]}"
else
echo "$PWD"
fi
}
Another special case
Les imagine your path in this kind:
/srv/dist/invoices-2019/data-2019-02-10/seq-123
To trim all part of path until first dash:
path_dash_Trim () {
local APATH;
IFS=/ read -a APATH <<< "$PWD";
APATH="${APATH[*]#*-}";
echo "${APATH// /\/}"
}
will render
/srv/dist/2019/2019-02-10/123
Fork performance issue
In order to reduce performance issue, there is a proper way to eliminate forks ( var=$(commnand) ): Set variable in function:
Simply replace
echo ${PWD#${left%/*}/}
by
printf -v $1 %s "${PWD#${left%/*}/}"
or better:
printf -v ${1:-myResult} '%s' "${PWD#${left%/*}/}"
Sample:
last_two_dirs() { local left=${PWD%/*};printf -v $1 "%s" "${PWD#${left%/*}/}" ;}
last_two_dirs result
printf -v $1 %s "$result"
or
path_parts() {
local APATH
IFS=/ read -a APATH <<<"$PWD"
if ((${#APATH[#]}>3)) ;then
printf -v $1 %s "/${APATH[1]}..${APATH[-1]}"
else
printf -v $1 %s "$PWD"
fi
}
and so on...
Then
export -f path_parts
PROMPT_COMMAND='path_parts PS1&&PS1+=" \\$ "'
or even simply dedicated function:
myPrompt() {
local APATH fmt='%s\[\e];%s\a\] $ '
IFS=/ read -a APATH <<<"$PWD"
if ((${#APATH[#]}>4)) ;then
printf -v PS1 "$fmt" "/${APATH[1]}..${APATH[-2]}/${APATH[-1]}"{,}
else
printf -v PS1 "$fmt" "$PWD"{,}
fi
}
PROMPT_COMMAND=myPrompt

Answer 4

Install MSYS2 tools, it has the tools you need.

Answer 5

function last_two_dirs ()
{
awk -F/ '{print ((NF>1)?$(NF-1)"/":"")""$NF}' <<< $PWD
}

Answer 6

You can simply use
pwd | sed -r 's|.*/([^/]+/[^/]+)$|\1|'
instead