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26-Sep-85 03:19:53-MDT,9618;000000000001 Return-Path: <unix-sources-request@BRL.ARPA> Received: from BRL-TGR.ARPA by SIMTEL20.ARPA with TCP; Thu 26 Sep 85 03:19:41-MDT Received: from usenet by TGR.BRL.ARPA id a005987; 26 Sep 85 4:45 EDT From: "c.bamford" <cjb@mtuxo.uucp> Newsgroups: net.sources Subject: cd commands that remember where you've been Message-ID: <989@mtuxo.UUCP> Date: 23 Sep 85 01:08:48 GMT To: unix-sources@BRL-TGR.ARPA

If you spend a lot of time prowling directory trees, the following Korn shell functions are very handy. They provide a version of the "cd" command that remembers which directories you've visited since login. Remembered directories are maintained in a stack and labelled with small integers; to cd to a directory you've already visited, it is only necessary to say something like: r 3 which makes the 3rd directory in the stack the current working directory, avoiding the necessity of retyping /horribly/long/directory/names.

These functions were inspired by the Csh pushd/popd/dirs commands, and go much further than the Ksh "cd -" command. Although they are written for the Korn shell, I have versions for Csh and /bin/sh if anyone has trouble with the conversions involved. Overly verbose documentation (including a little wall chart) appears in the shell file itself.

Cliff Bamford Consultant to AT&T Lincroft NJ room 113A-3L210 phone (210) 576 2133 ... ihnp4!mtuxo!cjb

Note: this is NOT an installation shell script - just put it in a file ------------------cut here--cut here--cut here------------------------ # # Ksh versions of the directory-stack management functions by bamford 21Sep85 # # The o,p,q,r,s commands replace cd. They maintain a stack of directories # visited by you since login. There are commands to visit (cd to) a new # directory, display the stack, reorder the stack, etc. # # To use these functions: copy this text to a file in your home directory # then insert the following lines in your .profile: # unalias r # ksh has a hardwired alias for r='fc -e -' # alias -x x='fc -e -' # now you can say "x ect=etc g" to fix last grep # . <this file name> # define the functions # alias cd=p # experts prefer alias cd=s # # The q command displays the directory stack. If your userid is foobar, and # your directory is /u/foobar, then this is what the q command displays # immediately after you logon: # q # 0=/u/foobar # # This means that the stack consists of a single directory numbered 0. # Directories on the stack are always numbered for easy reference, directory # number 0 is ALWAYS your current working directory. Now say you do two # cds in a row: # cd /usr/games # 0=/usr/games 1=/u/foobar # cd /news/spool/net # 0=/news/spool/net 1=/usr/games 2=/u/foobar # # Since cd is aliased to p (the PUSH directory command), your movement # thru the directory tree causes the stack to grow, always keeping the # current working directory at the top of the stack (position 0) and # pushing previous directories down the stack for possible future reference. # All the usual magic stuff works: # cd ~henry # 0=/v/henry 1=/news/spool/net 2=/usr/games 3=/u/foobar # cd # 0=/u/foobar 1=/v/henry 2=/news/spool/net 3=/usr/games # # Notice that last cd -- the opqrs commands never put a directory on the # stack if it's already there (it just moves the requested directory to # the top of the stack, making it the current working directory). # The r command is another way to reorder the stack. Without operands # it interchanges the top two directories: # r # 0=/v/henry 1=/u/foobar 2=/news/spool/net 3=/usr/games # # You can tell r to reach down further into the stack: # r 3 # 0=/usr/games 1=/v/henry 2=/u/foobar 3=/news/spool/net # r 3 # 0=/news/spool/net 1=/usr/games 2=/v/henry 3=/u/foobar # # The s command SWITCHES (replaces) the directory at the top of # the stack with the one you name: # s .. # 0=/news/spool 1=/usr/games 2=/v/henry 3=/u/foobar # s # 0=/u/foobar 1=/news/spool 2=/usr/games 3=/v/henry # # As shown in the last example, s without an operand means switch me # to my home directory -- which, in this case was already in the stack # so it got moved to the 0 (current working directory) position. # Finally, the o command POPs (removes directories) off the stack: # o # 0=/news/spool 1=/usr/games 3=/v/henry # # You can tell o to keep popping until the nth directory is at the top: # o 3 # 0=/v/henry # # None of the commands let you create an empty stack: # o 99 # 0=/u/foobar # # Which is an easy way to clean up the stack completely. # All of this is much harder to explain than it is to use. The following # chart really tells the whole story: # # command description # ------- ----------- # p X push directory X (default ) onto top of stack # s X switch (replace) top of stack with X (default ) # q display the stack (no operands allowed) # r n reorder - make the nth directory (default 1) top of stack # o n pop directories until the nth (default 1) is top of stack # # ####################End of Documentation################################# # # CDS is the directory stack CDSN is the highest valid index thereto # CDS[0]= let CDSN=0 export CDS export CDSN

function tellq ##### describe the q command { print "The q command displays the directory stack (queue)." print "It ignores all operands except ?, which produces this note." }

function q ##### display the queue { if [ $1xx = \?xx ] then tellq return fi let i=0 while [ -le ] do if [ ${CDS[]} ] then print -n "="${CDS[]}" " fi let i=i+1 done print -n \\n }

function oo ##### internal - pop 1 item off queue { if [ -eq 0 ] then CDS[0]= return fi let i=0 let j= while [ -le ] do let k=+1 CDS[]=${CDS[]} let i=+1 done unset CDS[] unset CDS[] let CDSN=${CDSN}-1 }

function tello ##### explain how to use o { print "The o n command pops the stack until the nth directory is top." print "If this leaves the stack empty, \ becomes single top." print "Usage: o (pop once)" print " or: o 1 (ditto)" print " or: o n (pop until the nth directory is at top)" print " or: o 99 (clean up stack completely)" }

function o ##### pop n items off queue (default is 1) { if [ $# -lt 1 ] then oo cd ${CDS[0]} q return fi if [ $# -gt 1 ] then print "o: too many parms [$*]" return 1 fi if [ $1xx = ?xx ] then tello return 1 fi case $1 in [!1-9] ) print "o: parm [$*] must be 1-9"; return 1;; esac let n=$1 while [ -gt 0 ] do oo let n=-1 done cd ${CDS[0]} q }

function chekstak ##### if stack contains $1 set to its index { let in=0 while [ -le ] do if [ $1 = ${CDS[]} ] then return 0 fi let in=+1 done return 1 } function rr ##### internal - switch top and CDS[$1], $1 is good { if [ $1 -gt ] then q return fi cd ${CDS[$1]} ##### if cd fails, we abort w/o changing CDS rrx=${CDS[0]} CDS[0]=${CDS[$1]} let rri=$1 while [ -gt 1 ] do let rrj=-1 CDS[]=${CDS[rrj]} let rri=-1 done CDS[1]= q }

function r ##### bring CDS[$1] to top of q { if [ $# -lt 1 ] then rr 1 return fi if [ $# -gt 1 ] then print "r: too many parms [$*]" return 1 fi if [ $1xx = ?xx ] then print "The r n command reorders the stack, bringing" print "the nth directory to the top." print "Usage: r 1 (interchange top and 1st directory)" print " or: r (ditto)" print " or: r n (bring nth directory to top)" return fi if [ $1xx = 0xx ] then q return fi case $1 in [!1-9] ) print "r: parms [$*] must be 0-9";return 1;; esac if [ $1 -lt 1 -o $1 -gt ] then print "r: parm [$*] out of range - max is " return 1 fi rr $1 }

function p #### push directory x onto stack { if [ $# -gt 1 ] then print "p: too many parms [$*]" return 1 fi if [ $1xx = ?xx ] then print "The p xxx command puts directory xxx on top." print "Usage: p /usr/bin (puts /usr/bin on top)" print " or: p (go to HOME directory)" print " or: p \~ (ditto)" print " or: p \`pwd\` (synch opqrs to real world)" return fi cd $1 #### if cd fails, exit w/o change pd=`pwd` if chekstak then r return fi let pi=+1 while [ -gt 0 ] do let pj=-1 CDS[]=${CDS[pj]} let pi=-1 done CDS[0]= let CDSN=+1 q }

function s #### switch $1 onto top of stack { if [ $# -gt 1 ] then print "s: too may parms [$*]" return 1 fi if [ $1xx = ?xx ] then print "The s xxx command replaces the top of stack with" print "directory xxx. A missing operand means HOME." print "Usage: s .. (cd to the parent of this directory)" print " or: s bin (go one directory lower)" print " or: s \~ (go to home directory)" print " or: s (ditto)" return fi cd $1 #### if cd fails exit without prejudice sd=`pwd` if chekstak then r return fi CDS[0]= q }