z/OS V1R9.0 UNIX System Services Command ... - Christian Grothoff

Usage notes
/etc/recover/$LOGNAME/VIt*
Contains the recovered text of the file that corresponds to the VIn* file
Rule: Using a TFS for vi temporary files will make it impossible to recover vi files
after a system crash. vi writes temporary files to TMP_VI or TMPDIR (or /tmp by
default), and if the system crashes, those files can be recovered by the exrecover
command, which automatically runs from /etc/rc. If the files are written to a TFS,
then they will be wiped out when the system is IPLed. See TMP_VI description
under Environment Variables section of this command.
1. To recover all the files in the temporary directory, this command must be run
with appropriate permissions (for example, superuser privileges) so the
recovered files can be stored in the /etc/recover directory with the appropriate
ownerships and permissions.
For example, the following is a shell script to recover the files from TMPDIR,
where TMPDIR is the default directory:
export TMPDIR=/tmp
exrecover
2. If it is invoked by a nonprivileged user (for example, a user who is not a root
user), then only those files owned by that user are recovered. Because vi and
ex create their working files in directories specified by the TMPDIR or TMP
environment variables, one of these environment variables must be set before
exrecover can be issued.
For example, the following is a shell script that recovers files from $HOME/tmp:
export TMPDIR=$HOME/tmp
exrecover
3. exrecover is also invoked by vi or ex when you issue the ex preserve
command or when exrecover receives a SIGHUP signal. The working files
created by vi and ex are found in a default temporary directory (such as /tmp)
or in the directory specified by the TMPDIR or in the directory specified by the
TMP_VI, TMPDIR, or TMP environment variable. Three working files are
created:
name_file
Contains the actual name of the vi file. The names of all name_files
begin with VIn.
line_table_file
Contains a dummy page followed by data that gives, in line number
order, the offset for each line of text in the corresponding
paged_text_file. The page size is typically 1K, but may vary on some
systems. The names of all line table files begin with VIl.
paged_text_file
Contains lines of text that are at most LINE_MAX bytes in length. Lines
shorter than LINE_MAX byte are ended by a newline. The names of all
paged text files begin with VIt.
4. You can also run the program by specifying name_file on the command line. For
example:
exrecover /tmp/VInaaaa.111 /tmp/VInbbbb.222 ...
exrecover daemon
exrecover searches for a name_file and tries to open the associated line table
and paged text files. If all these files are found, exrecover builds, from the line
table and paged text files, a text file and stores it in the directory
/etc/recover/$LOGNAME.
Chapter 2. Shell command descriptions 269