Converting DOS Batch Files to Shell Scripts

Quite a number of programmers learning scripting on a PC running DOS.

Even the crippled DOS batch file language allowed writing some fairly powerful scripts and applications, though they often required extensive kludges and workarounds.

Occasionally, the need still arises to convert an old DOS batch file to a UNIX shell script and vice versa. This is generally not difficult, as DOS batch file operators are only a limited subset of the equivalent shell scripting ones.

Converting a DOS batch file into a shell script is generally straightforward, and the result ofttimes reads better than the original.

Just to make your job easy, we are providing the differences between DOS and Unix scripting below.

Batch file keywords / variables / operators, and their shell equivalents:

Batch File OperatorShell Script EquivalentMeaning
%$command-line parameter prefix
/-command option flag
\/directory path separator
Err:520=(equal-to) string comparison test
!==!!=(not equal-to) string comparison test
@set +vdo not echo current command
**filename "wild card"
>>file redirection (overwrite)
>>>>file redirection (append)
<<redirect stdin
%VAR%$VARenvironmental variable
NOT!negate following test
NUL/dev/null"black hole" for burying command output
ECHOechoecho (many more option in Bash)
ECHO.echoecho blank line
ECHO OFFset +vdo not echo command(s) following
FOR %%VAR IN (LIST) DOfor var in [list]; do"for" loop
:LABELnone (unnecessary)label
GOTOnone (use a function)jump to another location in the script
PAUSEsleeppause or wait an interval
CHOICEcase or selectmenu choice
IF EXIST FILENAMEif [ -e filename ]test if file exists
IF !%N==!if [ -z "$N" ]if replaceable parameter "N" not present
CALLsource or . (dot operator)"include" another script
COMMAND /Csource or . (dot operator)"include" another script (same as CALL)
SETexportset an environmental variable
SHIFTshiftleft shift command-line argument list
SGN-lt or -gtsign (of integer)
ERRORLEVEL$?exit status
CONstdin"console" (stdin)
PRN/dev/lp0(generic) printer device
LPT1/dev/lp0first printer device
COM1/dev/ttyS0first serial port

Batch files usually contain DOS commands. These must be translated into their UNIX equivalents in order to convert a batch file into a shell script.

DOS commands and their UNIX equivalents:

DOS CommandUNIX EquivalentEffect
ASSIGNlnlink file or directory
ATTRIBchmodchange file permissions
CDcdchange directory
CHDIRcdchange directory
CLSclearclear screen
COMPdiff, comm, cmpfile compare
COPYcpfile copy
Ctl-CCtl-Cbreak (signal)
Ctl-ZCtl-DEOF (end-of-file)
DELrmdelete file(s)
DELTREErm -rfdelete directory recursively
DIRls -ldirectory listing
ERASErmdelete file(s)
EXITexitexit current process
FCcomm, cmpfile compare
FINDgrepfind strings in files
MDmkdirmake directory
MKDIRmkdirmake directory
MOREmoretext file paging filter
PATH$PATHpath to executables
RENmvrename (move)
RENAMEmvrename (move)
RDrmdirremove directory
RMDIRrmdirremove directory
SORTsortsort file
TIMEdatedisplay system time
TYPEcatoutput file to stdout
XCOPYcp(extended) file copy



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