deleting first line of a file using in-place editing

ranjan_jajodia has asked for the wisdom of the Perl Monks concerning the following question:

Dear Monks,
I need to delete the first line of a file, i.e, if a file's content were:

JohnGalt
DagnyTagart
HenryHankRearden
[download]

After editing it should become:

DagnyTagart
HenryHankRearden
[download]

I have tried the following command but it seems to delete all lines even though I did not put g(global) option:

perl -p -i -e "s/[^\n]*\n//" test.txt

Could any one tell me what is wrong over here and what is the correct way?

Regards
Ranjan

Comment on deleting first line of a file using in-place editing Select or Download Code

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Re: deleting first line of a file using in-place editing by davido (Cardinal) on Sep 08, 2005 at 02:37 UTC
The -p option causes printing to occur via an assumed `continue` block. `continue` blocks execute even if you short circuit the assumed loop with `next`, so it becomes somewhat of a contortion skipping the first line while using the -p option. One way to do it (using the -p option) would be to read the first line in a BEGIN{} block and do nothing with it, but that's silly because there's a better solution. If you really don't want to print one (or maybe several) of the lines, retake control over `print` by using the -n option instead of -p. `perl -ni.bak -e "print if $line++;"` [download] The preceeding snippet does an inline edit where the first line is not echoed back out to the output file again, but all subsequent lines are. Dave	[reply] [d/l] [select]
Re: deleting first line of a file using in-place editing by monkfan (Curate) on Sep 08, 2005 at 02:37 UTC
I learned this from merlyn. `perl -n -e 'print unless 1..1' your_file > outputfile` [download] Regards, Edward	[reply] [d/l]
Re: deleting first line of a file using in-place editing by sk (Curate) on Sep 08, 2005 at 02:39 UTC
`[sk]% cat test.txt JohnGalt DagnyTagart HenryHankRearden [sk]% perl -i -ne 'print if $. > 1' test.txt [sk]% cat test.txt DagnyTagart HenryHankRearden` [download]	[reply] [d/l]
Re: deleting first line of a file using in-place editing by greenFox (Vicar) on Sep 08, 2005 at 02:41 UTC
In the spirit of TIMTOWTDI... `perl -ni -e "print unless $. == 1" test.txt` [download] -- Murray Barton Do not seek to follow in the footsteps of the wise. Seek what they sought. -Basho	[reply] [d/l]
Re: deleting first line of a file using in-place editing by ranjan_jajodia (Monk) on Sep 08, 2005 at 02:44 UTC
Thanks Monks! The answers given by you work :-). Regards, Ranjan	[reply]


good chemistry is complicated, and a little bit messy -LW
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deleting first line of a file using in-place editing

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