"status" value for previous command:  $?


Command recall (tcsh)
    > !cmd:p
           \
           ":p" says "paste command in history, but do not execute"
      Then must up-arrow once to get command to edit.


Setting shell variables:
  o sh:
      > sts=$?
            \
            Note: no spaces allowed

  o csh:
      > set sts = $?
                \ \
                 Note: spaces are REQUIRED


"if" command  (see also "if" alternate, below)
  o sh:
            if (test -f filename) ; then  echo Woof ; fi
      OR    if [ -f filename ] ; then  echo Woof ; fi
                                      \
                          NOTE: all one line, no semi-colon after "then"

  o csh:
            if ( -d $1 ) then
               echo $1 is directory
            else if ( -e $1 ) then
               echo File $1 exists
            else
               echo $1 does not exist
            endif

"if" alternate (all shells?)
   > cmp -s file1 file2 && echo Files identical || echo Files differ
             \
              Note: each test appears to be implicitly (xxx == 0), so
                    first conditional is "true", strange to say.


Looping:
  o sh: (may be all one line)
            for i in ..list-of-words.. ; do
               echo $i
            done

  o csh: (must be on separate lines)
            foreach i ( ..list-of-words.. )
               echo $i
            end


Binary files:
    o ldd [filenames]
      Show resolution to all library dependencies

    o nm [filename]
      Searches for entry points and globals
      -r to show filename

    o strings [filename]
      Search for text strings in file


Differences:
    diff:   display differences between files
    sdiff:  side-by-side version of diff
    cmp:    location of first difference;  -s reports sts only (it's quiet)


Man pages to file:
    man test | col -b > test.man


File links:
   > ln -s ./existing_file_or_dir  xxx
            -- This creates the link "xxx"
   > rm xxx
            -- Removes the link only.  Original file/directory is ok.

Mounted file systems:
   > showmount -a birch.pppl.gov


Shared libraries:
  (see gibney$:[handbook]uxix_compile_link.mem)


Printers:
    lpq -Pname         :Check printer queue
    lpr -Pname         :Submit print requst
    lprm -Pname ids    :Remove ids from queue (get ids from lpq)
      ..also..
    lp
    lpstat