perl -e 'chop $x' perl -e 'chop FOO' Can't modify constant item in chop at -e line 1, at EOF Execution of -e aborted due to compilation errors. perl -e 'chop "BAR"' Can't modify constant item in chop at -e line 1, at EOF Execution of -e aborted due to compilation errors. perl -v This is perl, version 5.005_03 built for sun4-solaris