xargs command

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# 8  
Old 06-09-2011
your code is missing {} after -I see below :-

echo archDP105144_1_702159963.dbf| xargs -I{} cp {} `echo {}|awk '{sub(/DP1/,"TML");print}'`

# 9  
Old 06-09-2011
if there is only one file, using xargs is not optimal
you could just

cp archDP105144_1_702159963.dbf `echo archDP105144_1_702159963.dbf | awk '{sub(/DP1/,"TML");print}'`


f=archDP105144_1_702159963.dbf; cp $f "${f%%DP1*}TML${f##*DP1}"

# 10  
Old 06-09-2011
how about something simpler and w/o xargs...
ls -1 archDP1* | awk '{f=$0;sub("DP1", "TML");system("cp "f" "$0)}'

# 11  
Old 06-09-2011
Originally Posted by zam

The command below does not work. what I am doing wrong ?
For some reason second part of the xargs command is not does what I expect
If I get this working I intend to use it for multiple file rename later.
echo archDP105144_1_702159963.dbf|xargs -i cp {} `echo {}|awk '{sub(/DP1/,"TML");print}'`

with set -x
echo archDP105144_1_702159963.dbf|xargs -i cp {} `echo {}|awk '{sub(/DP1/,"TML");print}'`
++ echo '{}'
+ echo archDP105144_1_702159963.dbf
++ awk '{sub(/DP1/,"TML");print}'
+ xargs -i cp '{}' '{}'

Originally Posted by ahmad.diab
your code is missing {} after -I see below :-

echo archDP105144_1_702159963.dbf| xargs -I{} cp {} `echo {}|awk '{sub(/DP1/,"TML");print}'`


{} is not expanded by the shell. It is expanded by xargs after it starts executing. However, xargs cannot be exec'd until all of its command line arguments are known. This requires the shell to invoke a subshell to perform the command subsitution in backticks. Note that at this point xargs is not running. echo {} will always yield nothing but {}. In AWK, the sub() function has nothing to do since there's no DP1 to replace, and the output is the same as what's echoed. Then the shell, finally knowing the result of the command substitution, can execute xargs. xargs will then always be passed {} {} as its final two parameters.

In short, this approach cannot be made to work.

I suggest ctsgnb's suggestion:
Originally Posted by ctsgnb
f=archDP105144_1_702159963.dbf; cp $f "${f%%DP1*}TML${f##*DP1}"


Last edited by alister; 06-09-2011 at 01:35 PM..
This User Gave Thanks to alister For This Post:
# 12  
Old 06-10-2011
Thankyou ALL!Smilie

---------- Post updated at 05:07 PM ---------- Previous update was at 04:51 PM ----------

The code I ended up with!
for i in *.dbf
    echo "... renaming $i to ${i/DP1/TML}"  
    echo -e "y - continue / n - Skip / Ctrl+C - abort  --> \c"
    read ans
     if [ "$ans" = "y" ]; then
       mv $i ${i/DP1/TML}
       echo skipping $i

Last edited by Franklin52; 06-10-2011 at 06:17 AM.. Reason: Please use code tags
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