This is a Python program using vi/nano editor in bash.

1. Caesar ciphers form a group. Therefore repeated encryption with any key will recover the message. Use the repetition of key = 11 to encrypt the text. The proper decryption will be when 'e' is the most common letter and 't' is the second most common. Use the file caesar2.txt for input

caesar2.txt:

Rw cqn yanbnwc rwbcjwln, pxrwp kjlt cx cqn urena-yruu lralduja, R qjm cqn bhvycxvb, knhxwm juu vrbcjtn, cqn lqrno jvxwp cqnv knrwp "j pnwnaju mrbrwlurwjcrxw cx fxat xo jwh trwm."

Fqjc R bdoona rw cqjc fjh wx cxwpdn ljw cnuu. Oaxv vh njaurnbc rwojwlh R qjen knnw j vjacha cx rc. Jb j kxh, cqn mrbnjbn qjamuh nena unoc vn oxa j mjh. Cqnh mrm wxc twxf, cqnw, cqjc rc fjb vh urena. Vnmrlju blrnwln fjb rw j oja unbb jmejwlnm bcjcn cqjw wxf, jwm cqnh dbnm cx ydc rc mxfw cx ujirwnbb.

"Fqh, hxd btdutrwp urccun mneru, hxd," cqnh fxdum bjh, "pnc dy jwm mx bxvncqrwp oxa hxda urerwp, ljw'c hxd?" - wxc twxfrwp, xo lxdabn, cqjc R fjb ruu.

Jwm cqnh mrmw'c pren vn yruub; cqnh pjen vn ludvyb xw cqn brmn xo cqn qnjm. Jwm, bcajwpn jb rc vjh jyynja, cqxbn ludvyb xw cqn qnjm xocnw ldanm vn - oxa cqn crvn knrwp. R qjen twxfw xwn ludvy xw cqn qnjm qjen vxan noonlc dyxw vh urena, jwm vjtn vn onnu vxan jwgrxdb cx px bcajrpqc jfjh cqnw jwm cqnan, jwm mx fqjc fjb fjwcnm cx kn mxwn, frcqxdc odacqna uxbb xo crvn, cqjw j fqxun kxg xo yruub mxnb wxf.

Hxd twxf, rc xocnw rb bx - cqxbn brvyun, xum-ojbqrxwnm anvnmrnb jan bxvncrvnb vxan noorljlrxdb cqjw juu cqn mrbynwbjah bcdoo.