variable usage in sed commands - Revision history

Nighthawk at 20:12, 24 January 2018

2018-01-24T20:12:02Z

Nighthawk at 20:11, 24 January 2018

2018-01-24T20:11:44Z

Nighthawk at 20:11, 24 January 2018

2018-01-24T20:11:32Z

Nighthawk at 20:11, 24 January 2018

2018-01-24T20:11:02Z

Nighthawk: Created page with " Example print only lines 2 through 4 of file $ '''printf "one\ntwo\nthree\nfour\nfive\n" | sed -n '2,4p''''
two
three
four same using variables START=2 END=4 ..."

2018-01-24T20:10:39Z

Created page with " Example print only lines 2 through 4 of file $ '''printf "one\ntwo\nthree\nfour\nfive\n" | sed -n '2,4p'''' two three four same using variables START=2 END=4 ..."

New page

Example

print only lines 2 through 4 of file

$ '''printf "one\ntwo\nthree\nfour\nfive\n" | sed -n '2,4p''''
 two
 three
 four

same using variables

START=2
END=4

$ '''printf "one\ntwo\nthree\nfour\nfive\n" | sed -n "${START},${END}p"'''
 two
 three
 four

Examples that FAIL...

$ '''printf "one\ntwo\nthree\nfour\nfive\n" | sed -n "$START,$ENDp"'''
sed: -e expression #1, char 2: unexpected `,'

solution is to include the curly braces around the variable names

$ '''printf "one\ntwo\nthree\nfour\nfive\n" | sed -n '${START},${END}p''''
 sed: -e expression #1, char 3: unknown command: `S'

solution is to use double quotes in the sed commands so the variables are expanded

[[category:sed]]

@@ Line 13: / Line 13: @@
 $ '''START=2'''
 <br>$ '''END=4'''
+<br>$ '''printf "one\ntwo\nthree\nfour\nfive\n" | sed -n "${START},${END}p"'''
 $ '''printf "one\ntwo\nthree\nfour\nfive\n" | sed -n "${START},${END}p"'''
 <br>two
 <br>three

@@ Line 11: / Line 11: @@
 same using variables
-START=2
+$ '''START=2'''
-<br>END=4
+<br>$ '''END=4'''
 $ '''printf "one\ntwo\nthree\nfour\nfive\n" | sed -n "${START},${END}p"'''

@@ Line 12: / Line 12: @@
 START=2
-END=4
+<br>END=4
 $ '''printf "one\ntwo\nthree\nfour\nfive\n" | sed -n "${START},${END}p"'''

@@ Line 21: / Line 21: @@
 $ '''printf "one\ntwo\nthree\nfour\nfive\n" | sed -n "$START,$ENDp"'''
-sed: -e expression #1, char 2: unexpected `,'
+<br>sed: -e expression #1, char 2: unexpected `,'
 solution is to include the curly braces around the variable names

variable usage in sed commands - Revision history

Nighthawk at 20:12, 24 January 2018

Nighthawk at 20:11, 24 January 2018

Nighthawk at 20:11, 24 January 2018

Nighthawk at 20:11, 24 January 2018

Nighthawk: Created page with " Example print only lines 2 through 4 of file $ '''printf "one\ntwo\nthree\nfour\nfive\n" | sed -n '2,4p'''' two three four same using variables START=2 END=4 ..."

Nighthawk: Created page with " Example print only lines 2 through 4 of file $ '''printf "one\ntwo\nthree\nfour\nfive\n" | sed -n '2,4p''''
two
three
four same using variables START=2 END=4 ..."