http://codetunnel.com/tortoisesvn-basics-tutorial/#SetupBeyo ndCompare

Diff:
"C:∖Program Files∖Beyond Compare 3∖BComp.exe" %base %mine /title1=%bname /title2=%yname /leftreadonly

Merge:
"C:∖Program Files∖Beyond Compare 3∖BComp.exe" %mine %theirs "" %merged /title1=%yname /title2=%tname /title4="Output"

http://www.scootersoftware.com/vbulletin/showthread.php?3699-TortoiseSVN-integration&s=93b8a750bad1134d9f273ec5334a734c

Diff:
"C:∖Program Files∖Beyond Compare 3∖BComp.exe" %base %mine /title1=%bname /title2=%yname /leftreadonly

Merge (v3 Pro):
"C:∖Program Files∖Beyond Compare 3∖BComp.exe" %mine %theirs %base %merged /title1=%yname /title2=%tname /title3=%bname /title4=%mname

Merge (v3 Std):
"C:∖Program Files∖Beyond Compare 3∖BComp.exe" %mine %theirs /mergeoutput=%merged