YESTERDAY(1) YESTERDAY(1)
NAME
yesterday, diffy - print file names from the dump
SYNOPSIS
yesterday [ -abcCdDs ] [ -n daysago ] [ -date ] files ...
diffy [ -abcefmnrw ] files ...
DESCRIPTION
Yesterday prints the names of the files from the most recent
dump. Since dumps are done early in the morning,
yesterday's files are really in today's dump. For example,
if today is March 17, 1992,
yesterday /adm/users
prints
/n/dump/1992/0317/adm/users
In fact, the implementation is to select the most recent
dump in the current year, so the dump selected may not be
from today.
When presented with a path of the form /n/fs/path, yesterday
will look for dump files of the form
/n/fsdump/yyyy/hhmm/path.
By default, yesterday prints the names of the dump files
corresponding to the named files. The first set of options
changes this behavior.
-a Run acme(1)'s adiff to compare the dump files with the
named files.
-b Bind the dump files over the named files.
-c Copy the dump files over the named files.
-C Copy the dump files over the named files only when they
differ.
-d Run diff to compare the dump files with the named
files.
-D Run diff -n to compare the dump files with the named
files.
The date option selects other day's dumps, with a format of
1, 2, 4, 6, or 8 digits of the form d, dd, mmdd, yymmdd, or
Page 1 Plan 9 (printed 12/22/24)
YESTERDAY(1) YESTERDAY(1)
yyyymmdd.
The -n option selects the dump daysago prior to the current
day.
The -s option selects the most recent snapshot instead of
the most recent archived dump. Snapshots may occur more
frequently than dumps.
Yesterday does not guarantee that the string it prints rep-
resents an existing file.
Diffy runs diff(1) with the given options to compare
yesterday's version of each of the named files with today's.
EXAMPLES
Back up to yesterday's MIPS binary of vc:
yesterday -c /mips/bin/vc
Temporarily back up to March 1's MIPS C library to see if a
program runs correctly when loaded with it:
yesterday -b -0301 /mips/lib/libc.a
rm v.out
mk
v.out
Find what has changed in the C library since March 1:
yesterday -d -0301 /sys/src/libc/port/*.c
Find what has changed in the source tree today:
diffy -r /sys/src
FILES
/n/dump
SOURCE
/rc/bin/yesterday
/rc/bin/diffy
SEE ALSO
history(1), bind(1), diff(1), fs(4).
BUGS
It's hard to use this command without singing.
Doesn't work on January 1st.
Page 2 Plan 9 (printed 12/22/24)