Sponsored Content
Full Discussion: sed one Liner option -e
Top Forums Shell Programming and Scripting sed one Liner option -e Post 302942262 by TomG on Monday 27th of April 2015 02:26:52 AM
Old 04-27-2015
HP sed one Liner option -e

Hi,

I have the following command.(Delete all trailing blank lines at the end of a file.)

Code:
sed -e :a -e '/^\n*$/{$d;N;ba' -e '}'

I don't understand the logic of this command and also I don't understand why -e is used.
Can you please let me know the logic of this command and why three -e are used


Famous Sed One-Liners Explained, Part III: Selective Deletion of Certain Lines and Special Applications - good coders code, great reuse
here you can find the basic explanation for this command which i am not able to understand (82nd question)

Thank You

Last edited by TomG; 04-27-2015 at 04:03 AM..
 

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

Awk/Sed One liner for text replacement

Hi group, I want to replace the occurance of a particular text in a paragraph.I tried with Sed,but Sed only displays the result on the screen.How can i update the changes in the original file??? The solution should be a one liner using awk and sed. Thanks in advance. (5 Replies)
Discussion started by: bishnu.bhatta
5 Replies

2. Shell Programming and Scripting

Issue with a sed one liner variant - sed 's/ ; /|/g' $TMP1 > $TMP

Execution of the following segment is giving the error - Script extract:- OUT=$DATADIR/sol_rsult_orphn.bcp TMP1=${OUT}_tmp1 TMP=${OUT}_tmp ( isql -w 400 $dbConnect_OPR <<EOF select convert(char(10), s.lead_id) +'|' + s.pho_loc_type, ";", s.sol_rsult_cmnt, ";", +'|'+ s.del_ind... (3 Replies)
Discussion started by: kzmatam
3 Replies

3. Shell Programming and Scripting

Sed one-liner to print specific lines?

I need to print specific lines from a file, say 2-5, 8, 12-15, 17, 19, 21-27. How do I achieve this? (2 Replies)
Discussion started by: Ilja
2 Replies

4. Shell Programming and Scripting

Clarification needed for a SED one liner

I want to use SED to replace all new line characters of a file, I googled and found this one liner sed '{:q;N;s/\n//g;t q}' infile what do :q;N; and t q mean in this script? (6 Replies)
Discussion started by: kevintse
6 Replies

5. Shell Programming and Scripting

SED | Awk flat file one liner

sed awk one liner (2 Replies)
Discussion started by: jap2614
2 Replies

6. Shell Programming and Scripting

help with sed one liner

hey everyone, I want to remove some characters from a string that i have with sed. For example if my string is: a0=bus a1=car a2=truck I want my output to look like this: bus car truck So i want to delete the two characters before the = and including the =. This is what i came up with... (3 Replies)
Discussion started by: GmGeubt
3 Replies

7. UNIX for Advanced & Expert Users

Please explain this sed one liner

Can anyone explain the below sed oneliner? sed -e ':a' -e '$q;N;11,$D;ba' It works same as tail command. I just want to know how it works. Thanks ---------- Post updated at 11:42 PM ---------- Previous update was at 11:37 PM ---------- Moderators, Can you please delete this thread?... (0 Replies)
Discussion started by: pandeesh
0 Replies

8. UNIX for Advanced & Expert Users

sed one liner simialr to tail command

Can anyone explain the below sed oneliner? sed -e ':a' -e '$q;N;11,$D;ba' It works same as tail command. I just want to know how it works. Thanks (1 Reply)
Discussion started by: pandeesh
1 Replies

9. UNIX for Dummies Questions & Answers

sed one-liner

I have a data base of part numbers: AAA Thing1 BBB Thing2 CCC Thing3 File one is a list of part numbers: AAA234 BBB678 CCC2345 Is there a sed one-line that would compare a data base with and replace the part numbers so that the output looks like this? AAA234 Thing1 BBB678 Thing2... (5 Replies)
Discussion started by: jimmyf
5 Replies

10. UNIX for Dummies Questions & Answers

awk or sed one liner

I have a data base of part numbers: AAA Thing1 BBB Thing2 CCC Thing3 File one is a list of part numbers: XXXX AAA234 XXXX BBB678 XXXX CCC2345 Is there a sed one-line that would compare a data base with and replace the part numbers so that the output looks like this? XXXX AAA234... (7 Replies)
Discussion started by: jimmyf
7 Replies
SHTOOL-SUBST.TMP(1)					      GNU Portable Shell Tool					       SHTOOL-SUBST.TMP(1)

NAME
shtool-subst - GNU shtool sed(1) substitution operations SYNOPSIS
shtool subst [-v|--verbose] [-t|--trace] [-n|--nop] [-w|--warning] [-q|--quiet] [-s|--stealth] [-i|--interactive] [-b|--backup ext] [-e|--exec cmd] [-f|--file cmd-file] [file] [file ...] DESCRIPTION
This command applies one or more sed(1) substitution operations to stdin or any number of files. OPTIONS
The following command line options are available. -v, --verbose Display some processing information. -t, --trace Enable the output of the essential shell commands which are executed. -n, --nop No operation mode. Actual execution of the essential shell commands which would be executed is suppressed. -w, --warning Show warning on substitution operation resulting in no content change on every file. The default is to show a warning on substitution operations resulted in no content change on all files. -q, --quiet Suppress warning on substitution operation resulting in no content change. -s, --stealth Stealth operation. Preserve timestamp on file. -i, --interactive Enter interactive mode where the user has to approve each operation. -b, --backup ext Preserve backup of original file using file name extension ext. Default is to overwrite the original file. -e, --exec cmd Specify sed(1) command directly. -f, --file cmd-file Read sed(1) command from file. EXAMPLE
# shell script shtool subst -i -e 's;(c) ([0-9]*)-2000;(c) 1-2001;' *.[ch] # RPM spec-file %install shtool subst -v -n -e 's;^(prefix=).*;1 $RPM_BUILD_ROOT%{_prefix};g' -e 's;^(sysconfdir=).*;1 $RPM_BUILD_ROOT%{_prefix}/etc;g' `find . -name Makefile -print` make install HISTORY
The GNU shtool subst command was originally written by Ralf S. Engelschall <rse@engelschall.com> in 2001 for GNU shtool. It was prompted by the need to have a uniform and convenient patching frontend to sed(1) operations in the OpenPKG package specifications. SEE ALSO
shtool(1), sed(1). 18-Jul-2008 shtool 2.0.8 SHTOOL-SUBST.TMP(1)
All times are GMT -4. The time now is 11:10 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy