Fooblog

Someone asked if there was a way for diff to only show lines that are the same between 2 files. A little digging in the manpage for gnu diff got me this nice result:

diff --unchanged-line-format=%L --old-line-format= --new-line-format= FILE1 FILE2


This seems to work… but i’m open to other suggestions

Habbie pointed me to this one, but I thought it would be wise to write this down for future reference. The shell source command (.) in bash (and others) works like exec, not like open, (which you might be confused to think) in that it searches your $PATH for the argument, and if it can’t find the argument in the $PATH, it looks in $PWD

Demo:

PATH=/home/username/bin:/usr/bin:/bin:/usr/local/bin:…

$ echo “bin/meuk” > ~/bin/meuk
$ echo “home/meuk” > ~/meuk
$ cd ~

$ . meuk
bin/meuk
$ source meuk
bin/meuk

Update: Tested with bash / dash / ash / pdksh
All give the above result

From the manual:

source filename [arguments]
Read and execute commands from filename in the current shell
environment and return the exit status of the last command exeâ
cuted from filename. If filename does not contain a slash, file
names in PATH are used to find the directory containing fileâ
name. The file searched for in PATH need not be executable.
When bash is not in posix mode, the current directory is
searched if no file is found in PATH. If the sourcepath option
to the shopt builtin command is turned off, the PATH is not
searched. If any arguments are supplied, they become the posiâ
tional parameters when filename is executed. Otherwise the
positional parameters are unchanged. The return status is the
status of the last command exited within the script (0 if no
commands are executed), and false if filename is not found or
cannot be read.

Enabling the posix option in bash doesn’t change it’s behaviour, disabling sourcepath does:

$ shopt -u sourcepath
$ . meuk
/home/meuk