Learning the Korn Shell, 2nd Edition
by Bill Rosenblatt, Arnold Robbins

The unconfirmed error reports are from readers.  They have not yet been 
approved or disproved by the author or editor and represent solely the
opinion of the reader.

Here's a key to the markup:
        [page-number]: serious technical mistake
        {page-number}: minor technical mistake
        <page-number>: important language/formatting problem
        (page-number): language change or minor formatting problem
        ?page-number?: reader question or request for clarification

This page was updated March 26, 2007.


UNCONFIRMED  errors and comments from readers: 


(4)  The Korn Shell, 2nd paragraph, 1st sentence;
In following part:

... as part of AT&T's "Experimental Toolchest," meaning that ...

the quote and the comma must be switched:

... as part of AT&T's "Experimental Toolchest", meaning that ...


(22)  Background Jobs, first paragraph;
Second sentence begins with a lowercase letter and is poorly worded.

Current sentence begins:

any other commercial operating systems don't have...

Recommended change:

Other commercial operating systems do not have...


(30)  Table 1-7;
The second sentence of the Function Description for DEL or CTRL-? is:

"This is a common alternative setting. for the erase character"

Should be:

"This is a common alternative setting for the erase character"


{74}  10th line from top;
The output of

  print "The value of \$varname is \"$varname\"." (on 6th line)

should be

  The value of $varname is "bob".


(80)  Terminal types, first paragraph;
A space is missing between "like" and "more" on the last line of this paragraph.


(97)  Last paragraph, first sentence;
The sentence reads, "In addition, one other environment variable may be assigned to."
This is a sentence fragment.


(103)  function countargs definition;
Taking the called function's results into account, the contents of the function
countargs should be:
    print "$# args"
instead of:
    print "$# args."


(114)  2nd line;
2nd line on this page should be:

duction may be found in the second edition of ...

instead of:

duction may found in the second edition of ...


(121)  Table 4-9, 3rd operator;
the operator must be described as:

${variable%pattern}

instead of:

${{variable%pattern}


{122}  Last paragraph but one;
There is no difference between using %% or % in this case. The discussion would be
true if the example were:

objname=${filename%.*}.o

instead of:

objname=${filename%.c}.o

Furthermore, part of the last sentence but one should be (2 differences!):

..., so it would match .tab.c and evaluate to y.o rather than to y.tab.o.

instead of:

..., so it would match .tab.o and evaluate to y.o rather than y.tab.o.


(128)  2nd paragraph;
In the fourth line of the page => 'substituion', should be 'substitution'.


(151)  line 4;
this line should be:

the null string isn't a valid directory name, the condition will fail.

instead of:

the null string isn't a valid directory name, the conditional will fail.


(178)  topic 5, 2nd line;
color must be changed into colon


{181}  script code, last line but 6;
the ;; must be removed after the line

as "$filename" "$objname" ;;


[190]  190-193;
I couldn't get the directory stack system to work as advertised. Here's a variation
of the source that does work (this is a section from my .kshrc):

# should this be in this file?
export DIRSTACK="" # [CHANGE 1/3] THERE IS NO REASON TO
                   # HAVE STACK NON-EMPTY TO START WITH.

function dirs {
    print $DIRSTACK
}

function getNdirs {
    stackfront=''
    let count=0
    while (( count < $1 )); do
        stackfront="$stackfront ${DIRSTACK%% *}"
        DIRSTACK=${DIRSTACK#* }
        let count++
    done
}

function pushd {
    if [[ $1 == ++([0-9]) ]]; then
        # case of pushd +n: rotate n-th directory to top
        num=${1#+}
        getNdirs $num

        newtop=${stackfront##* }
        stackfront=${stackfront%$newtop}

        DIRSTACK="$newtop $stackfront $DIRSTACK"
        cd $newtop

    elif [[ -z $1 ]]; then
        # case of pushd without args; swap top two directories
        firstdir=${DIRSTACK%% *}
        DIRSTACK=${DIRSTACK#* }
        seconddir=${DIRSTACK%% }
        DIRSTACK=${DIRSTACK#* }
        DIRSTACK="$seconddir $firstdir $DIRSTACK"
        cd $seconddir

    else
        # normal case of pushd dirname
        dirname=$1
        if [[ -d $dirname && -x $dirname ]]; then
            bufpwd=$PWD # [CHANGE 2/3]: this is a new line
            cd $dirname
            DIRSTACK="$bufpwd $DIRSTACK"  # [CHANGE 3/3]: changed
            #print "$DIRSTACK"
        else
            print still in "$PWD."
            return 1
        fi
    fi
}

function popd { # pop directory off the stack, cd to new top
    if [[ $1 == ++([0-9]) ]]; then
        # case of oppd +n : delete n-th directory from stack
        num=${1#+}
        getNdirs $num
        stackfront=${stackfront% *}
        DIRSTACK="$stackfront $DIRSTACK"

    else
        # normal case of popd without arg
        if [[ -n $DIRSTACK ]]; then
            top=${DIRSTACK%% *}
            DIRSTACK=${DIRSTACK#* }
            cd $top
            print "$PWD"
        else
            print "stack empty"
            return 1
        fi
    fi
}



{191}  pushd() and popd() script;
The pushd() and popd() work, but are slightly different than the pushd and popd in
bash.

pushd fix:
If DIRSTACK is empty, pushd should push the current dir first.  The else clause of
the outside if statement should read:

 		if [[ -d $dirname && -x $dirname ]]; then
			DIRSTACK="$dirname ${DIRSTACK:-$PWD" "}"
			cd $dirname
			print "$DIRSTACK"
		else
instead of:
		if [[ -d $dirname && -x $dirname ]]; then
			cd $dirname
			DIRSTACK="$dirname $DIRSTACK"
			print "$DIRSTACK"
		else



popd fix:
In the else clause of the outside if statement should read:
		# normal case of popd without argument
		if [[ -n $DIRSTACK ]]; then
			DIRSTACK=${DIRSTACK#* }
			cd ${DIRSTACK%% *}
			print "$PWD"
		else
instead of:
		# normal case of popd without argument
		if [[ -n $DIRSTACK ]]; then
			top=${DIRSTACK%% *}
			DIRSTACK=${DIRSTACK#* }
			cd $top
			print "$PWD"
		else


(211)  3 lines before 'Here-Documents' header;
The line should end like this:

... to update data in a file "in place".

instead of:

... to update data in a file "in place."


(246)  1st paragraph, past the middle;
"..., we use the the cleverly named command command to"

should be changed into

"..., we use the cleverly named command command to"


(269)  2nd line;
... concatenating the the results of ...

must be changed into

... concatenating the results of ...