Thomas Schenk, Frankfurt am Main

VMS - UNIX survival guide

The brief command reference shown below hopefully helps you to survive a couple of days on your new OpenVMS or UNIX system.

Please note that VMS provides the Digital Command Language (DCL) only, whereas UNIX offers several shells like the Bourne Again Shell (bash), the Korn Shell (ksh), the C Shell (csh) and others. Depending on your shell selected the commands shown below may slightly differ.

VMS was once developed by

which now belongs to HP. From version 6 it was renamed to OpenVMS. You can find information on good ol' VAXes, PDPs and other great stuff on:
Documenting DIGITAL , PDP-11 and Digital trademarks.

Online documentation is available on:
VMS Help, OpenVMS beginner's FAQ, VMS Software and
Bash reference manual, Bash home page

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VMS - Unix survival guide

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General commands

UNIX (bash)	VMS (DCL)	remarks
man cp whatis cp apropos cp cp --help	HELP COPY	tell me how to copy
Cntrl-C	Cntrl-Y	stop current program
exit _or Cntrl-D	LOGOUT _or LO	terminate interactive shell
df -k	SHOW DEVICE D _or SH DEV D	show drives/partitions
ps aux	SHOW SYSTEM _or SH SYS	show processes
ps aux\|grep abc	PIPE SHOW SYSTEM \| _cont... SEARCH SYS$INPUT ABC	show process abc
kill -15 12345 kill -9 12345	STOP PROC /ID=12345	stop process no. 12345 -15 is better, -9 should only be used if the process doesn't react on -15

Directory commands

UNIX (bash)	VMS (DCL)	remarks
ls -la/abc/xyz/	DIR [ABC.XYZ]	list directory /abc/xyz/
cd /abc	SET DEFAULT [ABC] _or SET DEF [ABC]	change to directory /abc
cd /abc	SET DEF DKA200:[ABC]	VMS: change to directory abc on disk DKA200:
cd abc/xyz	SET DEF [.ABC.XYZ]	change to directory below current directory
cd /	SET DEF [000000]	change to root directory
cd ..	SET DEF [-]	change to directory above current directory
cd	SET DEF SYS$LOGIN:	change to home directory
pwd	SHOW DEFAULT _or SH DEF	show current directory
mkdir /abc/xyz	CREATE /DIR [ABC.XYZ]	create directory /abc/xyz
rmdir /abc/xyz	DELETE [ABC]XYZ.DIR;	delete directory /abc/xyz

File commands

UNIX (bash)	VMS (DCL)	remarks
cat abc.txt	TYPE ABC.TXT	list file contents
more abc.txt	TYPE/PAGE ABC.TXT	list file contents page by page
rm abc.txt	DELETE ABC.TXT; DELETE ABC.TXT;5 PURGE ABC.TXT PURGE /KEEP=3 ABC.TXT	delete highest version delete version no. 5 delete any but higest version keep 3 highest versions UNIX: delete file (there are no versions)
cp abc.txt /xyz/	COPY ABC.TXT DKA200:[XYZ]	copy file abc.txt into directory /xyz/
mv abc.txt xyz.txt	RENAME ABC.TXT XYZ.TXT	rename a file
ls -la abc.*	DIR ABC.*	list all files matching abc.*
find . -name *.txt	DIR [...].TXT	list all files matching *.txt in any subdirectory
find / -name *.txt	DIR DKA200:[000000...].TXT*	list all files matching *.txt in any directory
grep text abc.txt	SEARCH ABC.TXT "text"	search file for lowercase text
grep -i text abc.txt	SEARCH ABC.TXT TEXT	search again, but ignore case of text
diff abc.txt xyz.txt	DIFF ABC.TXT XYZ.TXT DIFF ABC.TXT ;-1	compare 2 files compare current and previous version

Program and script commands

UNIX (bash)	VMS (DCL)	remarks
. abc.bash	@ABC.COM	run script file in current context
abc.bash	SPAWN ABC.COM	run script file in a subshell
bash -x abc.bash	SET VERIFY @ABC.COM SET NOVER	switch on trace then run script then switch off trace
abc	RUN ABC.EXE	UNIX: run program abc. Search for it in environment vaiable $PATH VMS: run program abc found in current directory
/xyz/abc	RUN $DKA200:[XYZ]ABC.EXE	run program abc in directoy /xyz
/xyz/abc arg1 arg2	ABC=="$DKA200:[XYZ]ABC.EXE" ABC arg1 "arg2"	run same program with 2 arguments. VMS: first define symbol (dont forget $), then run program with uppercase arg1 and lowercase arg2
ls -la >xyz.txt	DIR /OUTPUT=XYZ.TXT	redirect output of shell command into a file
abc >xyz.txt	DEFINE/USER _cont... SYS$OUTPUT XYZ.TXT RUN ABC.EXE	redirect output of program into a file VMS: redirect output for one command only, then run program
abc \|grep -i xyz	PIPE RUN ABC.EXE \| _cont... SEARCH SYS$INPUT XYZ	search output of program for xyz ignoring the case VMS 7.x: PIPE allows UNIX style pipes

Alias and environment variable commands

UNIX (bash)	VMS (DCL)	remarks
alias abc	SHOW SYMBOL ABC	show alias or symbol abc
alias \|grep a	SHOW SYMBOL A	show aliases or symbols containing an a
alias rm='rm -i'	DEL=="DELETE /CONFIRM"	define an alias or symbol
alias rm='rm -i'	DELE=="DELETE /CONFIRM"*	same. VMS: Entering DEL or DELE calls the symbol. Entering DELET or DELETE calls the normal VMS DELETE command
export home='/abc/'	DEFINE HOME DKA200:[ABC]	define an environment variable or logical name
echo $home	SHOW LOG home	show environment variable or logical name
ls -la $home	DIR HOME:	use environment variable or logical name

UNIX commands and names are case-sensitive. VMS converts commands and names into uppercase letters. VMS commands can be abbreviated. For example DELETE, DELET, DELE, del and DEL are equivalent.

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