[ a 7-language polyglot in 323 bytes ]

C:
(*a/*/ % #)(PostScript)/Helvetica 40 selectfont 9 400 moveto show%v"f"a0
true showpage quit%#) 2>/dev/null;echo bash;exit #*/);int main()/*>"eb"v
%a*0)unless print"perl\n"__END__*/{printf("C\n");/*>>#;"egnu">:#,_@;,,,<
*)begin writeln(*\output={\setbox0=\box255}\eject\shipout\hbox{\TeX}\end
*)('pascal');end.{*/return 0;}

Pascal:
(*a/*/ % #)(PostScript)/Helvetica 40 selectfont 9 400 moveto show%v"f"a0
true showpage quit%#) 2>/dev/null;echo bash;exit #*/);int main()/*>"eb"v
%a*0)unless print"perl\n"__END__*/{printf("C\n");/*>>#;"egnu">:#,_@;,,,<
*)begin writeln(*\output={\setbox0=\box255}\eject\shipout\hbox{\TeX}\end
*)('pascal');end.{*/return 0;}

PostScript:
(*a/*/ % #)(PostScript)/Helvetica 40 selectfont 9 400 moveto show%v"f"a0
true showpage quit%#) 2>/dev/null;echo bash;exit #*/);int main()/*>"eb"v
%a*0)unless print"perl\n"__END__*/{printf("C\n");/*>>#;"egnu">:#,_@;,,,<
*)begin writeln(*\output={\setbox0=\box255}\eject\shipout\hbox{\TeX}\end
*)('pascal');end.{*/return 0;}

TeX:
(*a/*/ % #)(PostScript)/Helvetica 40 selectfont 9 400 moveto show%v"f"a0
true showpage quit%#) 2>/dev/null;echo bash;exit #*/);int main()/*>"eb"v
%a*0)unless print"perl\n"__END__*/{printf("C\n");/*>>#;"egnu">:#,_@;,,,<
*)begin writeln(*\output={\setbox0=\box255}\eject\shipout\hbox{\TeX}\end
*)('pascal');end.{*/return 0;}

Bash (shell):
(*a/*/ % #)(PostScript)/Helvetica 40 selectfont 9 400 moveto show%v"f"a0
true showpage quit%#) 2>/dev/null;echo bash;exit #*/);int main()/*>"eb"v
%a*0)unless print"perl\n"__END__*/{printf("C\n");/*>>#;"egnu">:#,_@;,,,<
*)begin writeln(*\output={\setbox0=\box255}\eject\shipout\hbox{\TeX}\end
*)('pascal');end.{*/return 0;}

Perl:
(*a/*/ % #)(PostScript)/Helvetica 40 selectfont 9 400 moveto show%v"f"a0
true showpage quit%#) 2>/dev/null;echo bash;exit #*/);int main()/*>"eb"v
%a*0)unless print"perl\n"__END__*/{printf("C\n");/*>>#;"egnu">:#,_@;,,,<
*)begin writeln(*\output={\setbox0=\box255}\eject\shipout\hbox{\TeX}\end
*)('pascal');end.{*/return 0;}

Befunge98:
(*a/*/ % #)(PostScript)/Helvetica 40 selectfont 9 400 moveto show%v"f"a0
true showpage quit%#) 2>/dev/null;echo bash;exit #*/);int main()/*>"eb"v
%a*0)unless print"perl\n"__END__*/{printf("C\n");/*>>#;"egnu">:#,_@;,,,<
*)begin writeln(*\output={\setbox0=\box255}\eject\shipout\hbox{\TeX}\end
*)('pascal');end.{*/return 0;}